[T-Mobile Samsung Galaxy Note II] PhxDroid86:
1) Would this second recovery(twrm) tool be better for the ROM I intend to use? Why or why not?

Answer: TWRP is similar to CWM but for some reason has seemed to work better for a selected few who claimed to have issues with CWM... it's all personal preference, but I use twrp personally

2) I have an unlocked T-Mobile handset, will when I flash the ROM enable the device to recognize my sim card, or will I have to unlock it again?

Answer: flashing roms doesn't affect the unlock status of your phone, so as long as you're following instructions then no worries here

3) Will a kernel be default installed with the ROM? If not, which would be best for Jedi 11, and is it flashed in a similar way after I flash the ROM itself? I would like the best in battery life without straining my device, if that's possible.

Answer: Yes, I believe Saber15.2 is included, I would go with the latest version of Saber (found in original development) as it generally gets updated before the rom itself.. you could also try perseus, some say great battery there as well

4) With this T-Mobile stock, I'm constantly having connection issues. Data just turns off randomly for short to long periods of time. Never had that before. What is a good modem to flash, and is it flashed in the same way?

Answer: I would tread lightly when it comes to modems, until you get the hang of the basics... so for now, make sure you don't mess with the modem when flashing roms and stay away from those that do. Also, stay inside these TMO forums for all your rom files is suggested as well, don't be one of those that flashed a ATT GNII Rom onto your TMO GNII and then wonder why your phones IMEI reads 0 and your phone doesn't get any service..FYI modems should only be flashed "in house" (only use TMO for TMO) unless you are switching carriers or traveling abroad

5) How exactly does one flash add-ons? Kernels, settings, modems...etc. I've yet to find any place with an explaination. It's just experienced users talking to experienced users; so steps get left out.

Answer: When it comes to the Jedi's Goody Bag add-ons you can just flash separately once your phone is done booting after initial rom flash. Kernals, as mentioned before, can be found in various threads but be sure to check compatibility first, as some roms require/work better with some kernels, and if they aren't compatible you could boot loop, modems is more advanced so until your ready, I'd leave yours alone.. Also should say look into EFS/Modem backup/restore apps and programs like Andromizer, QPST, etc and also TWRP backs up these as well

6) If I am told to use another recovery tool (TW-...something), could I still replace it now? Or would I have to uninstall Nandroid and other Root required apps first?

Answer: yes, the files (zips) that you download, like roms, kernels, add-ons, other mods, themes, etc, can be used for either TWRP or CWM... but if the OP of the zip recommends one over the other than don't be surprised there is any stability issues... Also, CWM backups can't be flashed through TWRP and vice versa, so if you are going to switch from CWM to TWRP than make sure you make all new backups