You want language on the contract preventing the seller from mortgaging the property, language allowing you to actually use the property while it is under land contract.  

I hesitate because this opportunity requires a $3,000.00 fee upfront to prevent tire kickers/time wasters.

I am not aware of a mortgage guideline that would prevent you from qualifying because your self employment income is too high.

That way if you get a booking on one it blocks off the calendar on the other to prevent two different people on two different sites from booking same dates.

I've also had to fly out to places to prevent project managers from getting banned from projects and to try to bring the project back on schedule after months of delays and change orders.

This prevents any accusations of me stealing money from a tenant or messing up their payment schedule.You could give your tenants a deposit slip and they can set up direct deposit or deposit the payment manually at your bank.  

I know that an ejectment can cost as much as $2,500 so is it worth it to go up to that to prevent property damage, removal of appliances, etc.?

If I don't know how to fly a plane a license won't prevent catastrophe. they also have crews and subs and a realistic view on actual cost and time.

A PM is suppose to prevent that from happening or troubleshoot.

And, that might prevent you from moving out of your primary residence at a future point.