I am one of the co-founder of Host that you mentioned. 

But we dont discourage co op or try to steal clients from other agents..

I am not aware of any PM co that charges the same fee for the original placement.

Pay close attention to the capital stack, how much debt there is, how much preferred equity there is, how much the GP is co-investing, how much they project rents to rise organically every year, what exit cap rate they're assuming, how much cash reserves the property/investment will have, how much does the deal returns change when you add 50-200 bps to the cap rate, what is your breakeven occupancy and exit cap rate, and a bunch more. 

Purchase price: $560,000 Cash invested: $56,000 Co-sign investment.

I am new to AirBnb co-hosting & currently oversee two properties listed on airbnb.

Something like co-hosting STRs, real estate photography or video (including drone), something in the trades if you have those skills, part time agent, etc.

I need a co-signer and I want to use an fha loan.

These properties are all within 1-3 months of completion and the investor does not close until the CO is revived.  

Prices skyrocketed right after I bought but the market is slowing there just like here in Colorado.