Vacancy and management will be the same portion of income no matter the amount of rent or FMV.Where you can drive down the expenses is as you get into larger (more units) properties, efficiencies of scale start to kick in.

Ensure the rental demand is there and you are comfortable holding the property long-term.

Make sure each deal you improve parts or all of your process and you'll be able to find an efficient way to identify, qualify, finance, acquire, and manage your deals.Find a way to get your first deal with the resources and network you currently have and through experience you'll expand your knowledge, skills, resources, and network as you go.

This is largely so that they can ensure life safety measures are being satisfied in these larger buildings. 

Whenever you are buying a property out of state you should do a few things to ensure it's as smooth as possible.Don't buy in the roughest neighborhood in the urban core.

What apps or resources are other investors/wholesalers utilizing to save time and make their tasks/processes more efficient?

Are you doing this personally or does the debt belong to an LLC that controls the property and you just have the responsibility of ensuring it gets repaid?

Can you recommend any great quality, efficient decently priced trades/GCs?

My private money lenders have put all their loan amounts on the HUD/Closing statement - that way they ensure they get paid when we refinance or in the unfortunate event we don't pay the loan.If these are smaller amounts for repairs, my private money lenders still require it to be on the HUD/Closing statement but they'll cut me a check(s) throughout the rehab. 

It seems likely your loan officer will want to ensure formal leases are in place to reach any kind of real value.