I am not a legal expert, and state and local laws are consistently changing. With that in mind, it would be in your best interest to seek local guidance from law enforcement or legal council.
All picatinny rails are a standard width so you just need a M-LOK picatinny rail that is at least 5" long.
Please email us at techsales@opticsplanet.com regarding your question with the Magpul AFG1 Angled Foregrip.
Yes. The Magpul AFG1 Angled Foregrip will attach to any picatinny/1913 underside rail. Any Hi-Point Carbine with a picatinny rail will be able to use this grip.
The AFG 2 has a few different design features to make it more ergonomic.
This one will not. You will need the Magpul MLOK AGF, which will be compatible with the MOE AKM Handguard.
https://www.opticsplanet.com/magpul-industries-angled-foregrip-mlok.html
It will fit the picatinny rail, but the 5.5" length may not work. Measure the space you're working with and if it is less than the 5.5" inches the AFG1 requires, check out the Magpul AFG2.
https://www.opticsplanet.com/magpul-afg2-angled-foregrip.html
Yes, the Magpul AFG1 will fit the Keltec Sub2000 Gen2 picatinny rail.
There are a few variants of the Scorpion Evo 3 S1, but it looks like most people are running the AFG 2 or MLOK AFG, depending on the configuration of their handguard. The AFG 2 fits Picatinny rails but is about an inch shorter than the AFG 1.
https://www.opticsplanet.com/magpul-afg2-angled-foregrip.html
Total length is 5.55".