FreedomPop 5Gb Yearly Deal

Ok, hoping someone here is familiar with what this is and how it works, I use FP for data only and it's the Sprint version. For this discussion, please note I care about IOS only. And also please note I don't want to hear about GV, not going to use it.

So, my understandings are this is AT&T network, which means I'll have great coverage most everywhere. Visual Voicemail is included. I believe though it's all VOIP? And I believe the FP app integrates with CallKit. So, that should mean I can dial from the phone or contacts (not FP app), and, calls coming in should ring in the phone just as any non VOIP call. If a message is left, is the visual indicator in the phone app, or, FP app only?

MMS is also included. So, for SMS and MMS, do they go via AT&T gateway (which allows me to use messages app for most everything since all but 2 people I know are iPhone), or, only in the FP app?

When my current plan expires, considering using this plan, don't care that it's VOIP per se, I have very few calls.

Anything else I should know?

Yes, VoIP.

Yes, iOS CallKit support. Incoming calls integrated with native phone app (eg; call history). Tapping on received/missed call in native phone app call history will dial via FP app. In native Contacts, long press on phone icon to bring up CallKit apps.

No native visual voicemail, only through FP app.

No native SMS/MMS, only through FP app.

You can only use AppleID for iMessages.

Thank you, all makes sense. Can you purchase any FP addons for the plan? Can you do tethering?

Does the FP app now work well with MMS, group messages with all carriers, etc.? Any limitations?