My theory is people are looking to move outside of cities to an area of more space and less restriction.

There are currently no rental restrictions, in fact the HOA has basically been completely silent for years. 

Are you restricted at raising the rent 5% a year until you reach market?

There are some significant restrictions, but it is possible.   

It’s in the county so there’s not a lot of restrictions.

When you reinvest/flip your cash plus the friends, you get your cash back again, plus the first friends, plus new friends.3 - Your cash should be restricted to the DP only. 

Your mortgage lender can help you with this, and will likely ask for a copy of the settlement statement from the refi you just did to submit with form 26-1880 request for one-time restoration of entitlement.The max cash-out allowed under Fannie/Freddie is restricted to 75% loan to value on a 1-unit investment property.  2-4 unit homes have a max 70% LTV under Fannie/Freddie for investment cash-out refi's. 

, is that as an agent, you have extra restrictions that you don't as just an investor that might not make it worth it. 

What's the process like for raising rent to market value year after year (any restrictions about this)?

The market is, and has been insane since the covid restrictions relaxed late last summer.