[Moto G 2015 Q&A, Help & Troubleshooting] FNetV1:
Thanks for your help, but the first app, Roam Control version 1.7.0 did not work, I am running Android version 6.0.1 Marshmallow and the last version of android for the version 1.7.0 fo that app to work based on my google research and what other members where reporting was Android Ice Cream Sandwich (Android Version 4.0.4) to Possibly Android Jelly Bean (Android Version 4.1.2) as that version same in around mid 2013 where these version were at its epicenter, there were a user on another xda thread complaining tthat Roam Control V1.7.0 stopped working after upgrading to Android Jelly Bean, so not even in KitKat (v4.4.4) would this particular version work. However, the latest version to ever be released for Roam Control was v2.11.1 and this particular version is reported to said to work in Android v4.4.4 (KitKat) however KitKat was the latest version of android when that version of Roam Control was released before the Developer abandoned the project and the product became unavailable to purchase and its activation license server went offline potentially screwing customer who legitimately purchased this app, but there is a problem that prevents me from testing version 2.11.1 of Roam Control to see if it would work in Android 6.0.1, its License server shows code 9 (which in this context really means unable to reach license server) when you install that .apk so that very old version you posted here is actually the last version to work without any license key check, however it also requires a very very old version of android to make it work, once that is not available for the Moto G 2015.

Regarding the second app you linked, the Roaming Control Xposed module, well I think that app, with a little fiddling around with the radio band (*#*#4636*#*#) was able to keep the phone roaming for an extended period of time, however roaming is only limited at 1xRTT (2G speeds) and only works at that radio mode, if radio mode left at 4G/CDMA it would connect naturally to Sprint's non roaming native 4G LTE tower, but if I switched radio mode to CDMA (under settings where it says Sprint Only, 4G/CDMA, CDMA, 1x, and Automatic), normally under Sprint switching to CDMA gets you the EvDo tower connection (3G), but with roaming, and roaming has only been possible after changing the radio band to "Cellular 800 MHz", EvDo /eHRPD is ignored, Radio gets "breathed out" from the tower until zero bars, then it connects to 1xRTT in full bars and after about 10 seconds it connects, so roaming works only at 2G speeds. Well that sucks.

Further researching why I am only able to roaming 2G speeds I took it to more googling which revealed the answer why its working only in 1xRTT mode. The reason is Sprint's roaming agreement with Verizon which is 2G speeds so, this means that the vast majority of Sprint residential customers (with a very limiting exception of Corporate customers and a few who have a 3G roaming agreement and enforced by their PRL's first two integer segment) can only roam in 2G (1xRTT) mode, and the only "fix" for this is to manually change the phone's PRL to another one that actually gives you the "right" to roam in 3G/EvDo mode, however it may not be possible to actually roam on Verizon's 4G LTE tower for the reason that LTE is controlled entirely by a different technology, called GSM, where CDMA is only used for up to EvDo speeds so this limits "roaming" to a theoretical maximum of EvDo speeds, the highest level that CDMA technology offers..

Now, actually changing my phone's PRL manually has proven to be a problem, it is just not possible not at least without knowing the MSL code first and getting that code under my current circumstances might not be even possible.

Currently with Sprint I am getting faster speeds at Sprint's 3G towers than in Sprint's 4G LTE, as I said in the OP, My 4G LTE speeds is abysmally slow throught the grand part of the day, but if I force my phone to connect to EvDo mode, my speeds can be up to 2.5 MBPS which is a great improvement by a factor of multiples of the speeds that I can get in my house using LTE mode. My idea of wanting to roam in Verizon's tower was to be able to roam in LTE speeds at Verizon's tower, but knowing that its not even possible and Sprint's 3G tower being acceptable in terms of what a 3G connection should deliver in terms of speeds then I shall keep on using Sprint under 3G mode. It is a shame that Sprint's 4G LTE tower is either broken or over congested in my area.