I have many firiends they are using this site without any problem for years even they are living in USA and they never need to send KYC documents or any thing for any verification as they are doing nothing wrong with this.
I think it doesn't matter. In Betcoin.ag rules it's clearly written that they don't accept players from USA, so, your friends break their rules and they are risking to get their account closed. While OP is looking for sportsbook who actually allows people from USA to play without breaking rules or using VPN to bypass restrictions.
I have checked your list and almost all sportsbooks, except Bovada isn't known for me. I'm not sure, is it good idea to play in not well known sportsbook without solid reputation. Before joining it, I advice OP to make research about it.