It's best to be conservative when thinking of prospective numbers.

What can I do to deter them from coming in?

The problem I’m seeing is that there are a lot of single family homes on the market that could be good prospective deals but since there is a surplus I’m concerned about vacancy.

Is there any ways I can have the property listed now and have schedule viewing for future prospective tenant?

As for being screwed because of tenants - That happens for sure but if that's whats going to deter you from becoming financially free then maybe Real Estate isn't for you.

If he had no immediate prospect of higher income I'd agree, but he showed me $12k in savings, plenty to cover the gap till his raise, and his mother offered to co-sign. 

It wasn't impacting the rent or deterring renters.  

@Colleen Ross I've had it done two different ways when it's an apartment complex or PM company. 1) Have the prospective tenant sign a form allowing for the release of information2) Have the prospective tenant send a form requesting they fill out information and send to the fax number or email listed which would come directly to me. 

. - Self managing a couple units is a great way to learn the business.Property Management Software - check out something like Cozy.co - it helps you list/market your units for rent, lets prospective tenants apply online and does background & credit checks, then once you place a tenant they can pay online along with submit maintenance requests.

If they aren’t willing to do this, move on to other prospects.