You should be fine doing what you want on Linux. Just make sure everything works before installing completely. There is a liveUSB mode that let’s you try it before you install.
Mint and PoP os are good ones to try.
Can also check out Zorin os which is pretty good too but doesn’t update as often.
I don’t know the details but both use services from the carrier. I think google hosts for the carriers but there are checks thats rely on the carrier. If you look at the details for google messages it address specific URLs based on the carrier.
For iPhone its all carrier depend. If the carrier doesn’t support it, iPhone will not have it.