We charge a $200 non-refundable deposit for pets at lease signing and $50/month pet rent (on rents around $2000).Late fees are $10/day starting at the 5th of the month.My historic vacancy rates are around 1-2% (20 years) - I expect to sustain that level.

Lots of tenants will try to use it as leverage at a later date....when they leave and you dont give the full deposit back.....when they are late on a payment..... when they screw something up and you make them pay for the repair. 

But they are arguing that there is no written checklist at the start of the agreement and thus we cannot retain any money from the deposit.

This property will have property manager to pay all expenses and deposit rents. 

Needless to say they can't count on their security deposit (they've been asking for it!

Get the deposit back and walk away as fast as you can.

What does your local law say about security deposit returns?

And the flips/BRRRR are going to take 5 months ish.As for whats advertised, yes you have endless resources to answer every questions you could think of or problem you come across. 

Renting requires a deposit that you hopefully get back.

Besides, I can offset that risk with requiring first and last month Rent in addition to security deposit.Only Tenants who can submit security deposit and all rent money can sign the lease.