[Sony Xperia T, TL, TX, V] FlamurKasa:
Just got it it running with Magisk on my Xperia T. Here is step by step of what I did for anyone it might help:

I did not have TRWP so I decided it is time to get it. I had root so I just got the Official TWRP app from the app store, selected my phone from the list, downloaded theTRWP 3.1 img file and flashed it through the app (note: I had to retry downloading several times but it did work).

Then I got these files:

The

ROM zip (link in first post of this thread)

Boot Bridge for Sony ELF

Latest Magisk version (v12 for me)

Gapps 7.1

When I had everything downloaded, I opened the ROM's zip, and deleted magisk.zip from the /magisk folder (this is done inside the zip - no extraction needed, using 7-Zip in my case). Copied ROM's zip to my SD card.

Next I renamed the Magisk zip to install.zip and moved it to the /install folder inside of BootBridge-SonyELF.zip (confirm when prompted to overwrite). Copied BootBridge-SonyELF.zip to my SD card.

Copied BootBridge-SonyELF.zip to my SD card.

Copied Gapps zip to my SD card.

Moment of truth:

0. Rebooted to recovery (TWRP)

1. Wipe > Advanced wipe > selected: Dalvik/ART Cache, cache, Data, Internal Storage

2. Install ROM zip (wiped cache after install)

3. Install BootBridge-SonyELF.zip (wiped cache after install)

4. Install Gapps zip (wiped cache after install)

5. I had no errors during any installation so I rebooted to system

6. First boot took me a while (went to buy something at the store and came back home, wasn't done yet)

7. Went through the Google setup. System was mostly not responsive the first 10 minutes or so, including the keyboard and everything taking a while especially the very first time they appear. Let things things initialize and sync for a bit.

8. a few hours later things are butter smooth :)

I have installed any app yet nor checked the Magisk manager. I will update this post later when I do (if I don't forget).

Note: I used a gapps-config to customised what will installing gapps add, remove and replace. You can read more about that here. I will paste my config below in case you want to see how it looks:

# Remove apps (uncomment a line to remove the app)
# CMAccount # Remove CM Account
# CMBugReport # Remove CM Bug Report
# CMAudioFX # Remove CM AudioFX
CMFileManager # Remove CM File Manager
CMMusic # Remove CM Music
# CMScreenCast # Remove CM ScreenCast
# CMSetupWizard # Remove CM Setup Wizard (see Notes for CMSetupWizard)
# CMUpdater # Remove CM Updater
# CMWallpapers # Remove CM Wallpapers
CMWeatherProvider # Remove CM Weather Underground

DashClock # Remove DashClock Widget (found in certain ROMs)
# Hexo # Remove Hexo Libre CM Theme
LRecorder # Remove LineageOS Recorder
# LSetupWizard # Remove LineageOS Setup Wizard
OmniSwitch # Remove OmniSwitch recent apps switcher replacement

BasicDreams # Remove Basic Dreams Wallpaper
Galaxy # Remove Galaxy (also known as BlackHole) Wallpaper
HoloSpiral # Remove Holo Spiral Wallpaper
NoiseField # Remove Noise Field Wallpaper
Phasebeam # Remove Phasebeam Wallpaper
PhotoPhase # Remove Photo Phase Wallpaper
PhotoTable # Remove Photo Table Wallpaper

# Browser # Remove Stock Browser
# CalculatorStock # Remove Stock Calculator (automatically removed when Google Calculator is installed)
# CalendarStock # Remove Stock Calendar (automatically removed when Google Calendar is installed)
# CameraStock # Remove Stock Camera (Including CAF's camera application, Snap)
# ClockStock # Remove Stock Desk Clock (automatically removed when Google Clock is installed)
Email # Remove Stock Email Client
ExchangeStock # Remove Stock Exchange Services (automatically removed when Google Exchange Services is installed)
MzFileManager # Remove Stock FlymeOS File Manager
MzPay # Remove Stock FlymeOS Pay system (because MzPay services works only in China)
MzSetupWizard # Remove Stock FlymeOS SetupWizard
MzUpdater # Remove Stock FlymeOS Updaters
MzWeather # Remove Stock FlymeOS Weather (because MzWeather service work only in China)
FMRadio # Remove Stock FM Radio (not found on all devices or ROMs)
Gallery # Remove Stock Gallery
# KeyboardStock # Remove Stock Keyboard (automatically removed when Google Keyboard is installed)
# Launcher # Remove Stock Launcher(s)
LiveWallpapers # Remove Stock Live Wallpapers
# LockClock # Remove Stock Lockscreen Clock Widget
# Studio # Remove Stock Movie Studio
# TagStock # Remove Stock NFC Tags (automatically removed when Google NFC Tags is installed)
# PicoTTS # Remove Stock PicoTTS
PrintServiceStock # Remove Stock Print Service Recommendation Service (automatically removed when Google Print Service Recommendation Service is installed)
SimToolKit # Remove Stock SimToolKit
SoundRecorder # Remove Stock Sound Recorder
# MMS # Remove Stock SMS (automatically removed if Google Messenger and/or Hangouts is installed)
# StorageManagerStock # Remove Stock Storage Manager (automatically removed when Google Storage Manager is installed)
# Terminal # Remove Stock Terminal
# Themes # Remove Stock Theme Engine (will break the Settings Entry and can cause unexpected reboots on some ROMs)
# VisualizationWallpapers # Remove Stock Visualization Wallpapers
# WhisperPush # Remove Stock WhisperPush support

# Pico+
#DialerFramework # Install Dialer Framework
#CalSync # Install Google Calendar Sync (except if Google Calendar is being installed)
#GoogleTTS # Install Google Text-to-Speech (Micro+ on 5.0-, Pico+ on 6.0+)
#PackageInstallerGoogle # Install Google Package Installer

# Nano+
#FaceDetect # Install FaceUnlock
#FaceUnlock # Install FaceUnlock
Search # Install Google Search (including includes Hotword, excluding excludes GoogleNow and PixelLauncher)
#Speech # Install Offline Speech Files
Hotword # Install OK Google Hotword Enrollment

# Micro+
#Gmail # Install Gmail
#CalendarGoogle # Install Google Calendar
ExchangeGoogle # Install Google Exchange Services
GoogleNow # Install Google Now Launcher (requires Search)
# GoogleTTS # Install Google Text-to-Speech (Micro+ on 5.0-, Pico+ on 6.0+)

# Mini+
#CalculatorGoogle # Install Google Calculator
#ClockGoogle # Install Google Clock
Maps # Install Google Maps
#TagGoogle # Install Google NFC Tags
Photos # Install Google Photos
GooglePlus # Install Google+
Hangouts # Install Hangouts
YouTube # Install YouTube

# Full+
#Chrome # Install Google Chrome Browser
CloudPrint # Install Google Cloud Print
Docs # Install Google Docs
Drive # Install Google Drive
Fitness # Install Google Fit
Keep # Install Google Keep
NewsWidget # Install Google News & Weather
Books # Install Google Play Books
PlayGames # Install Google Play Games
Movies # Install Google Play Movies & TV
Music # Install Google Play Music
NewsStand # Install Google Play Newsstand
Sheets # Install Google Sheets
Slides # Install Google Slides
Talkback # Install Google TalkBack

# Stock+
#CameraGoogle # Install Google Camera
#ContactsGoogle # Install Google Contacts
DialerGoogle # Install Google Dialer
#KeyboardGoogle # Install Google Keyboard
#Messenger # Install Google Messenger (except on tablet devices)
#PixelIcons # Install Google Pixel Icons
#StorageManagerGoogle # Install Google Storage Manager
VRService # Install Google VR Services
#WebViewGoogle # Install Google Webview
PixelLauncher # Install Pixel Launcher (requires Search and Wallpapers)
PrintServiceGoogle # Install Print Service Recommendation Service
Wallpapers # Install Wallpapers

# Super+
AndroidPay # Install Android Pay
DMAgent # Install Google Apps Device Policy
GCS # Install Google Connectivity Services (excluding also excludes ProjectFi)
Earth # Install Google Earth
Indic # Install Google Indic Keyboard
Japanese # Install Google Japanese Input
Korean # Install Google Korean Input
Pinyin # Install Google Pinyin Input
Street # Install Google Street View
Translate # Install Google Translate
Zhuyin # Install Google Zhuyin Input
ProjectFi # Install Project Fi by Google