Bro, I have the same EXACT issue! People do not "GET IT"...
On LG V-10 Unlocked using Cricket as well. I think its because Verizon allows text via wifi, it won't let our MMS go through as its trying something with the wifi which won't work. I already bought the "unlocked phone" added custom cricket apn, even changed to this, read:
https://www.reddit.com/r/NoContract/comments/3paxri/another_day_with_cricket_wireless_mms/
I am rooted, surprise there is no way to force LTE and WCDMA to get the LTE I pay for on this unlocked Verizon LG-V10. However, that is the least of my worries, I just want to get MMS and send them when on wifi at home without having to toggle it on and off, makes zero sense, everybody is blaming Cricket, it just may be the Verizon phone and since I am rooted, must be a way to fix it with a script to tell it to use DATA to send NOT WIFI!
However, I have yet to find it and the blame is on Cricket STILL..
What did you end up doing or figuring out? I am going CRAZY...
PS: Love the V10 (Stayed on 5.1.1 I could root) and if I knew would of been an issue, would have bought an AT & T version but saw this and said unlocked, everything else works. Its nuts! Zero answer. I see something saying mms setting in titanium I am about to freeze it to see if it screws me or not, it must be versions software side of doing things? People keep saying use Textra app or Chomp but I do not want to. I like Signal. I would settle for the on board messenger if it worked with MMS while on wifi. If I change one setting to get 4g I can not call or text and the other vice versa as tried everything.
Main issue: I just want to remain on wifi auto when in bounds but have mms send via data like it should and receive auto when they come in versus making me turn off my wifi and using up all my data as forget to turn it back on for something else. MAKE ZERO SENSE. I want to be schooled!! I hope somebody schools me here on XDA!