Without tenants it's easier to show the property and the condition can look better than if tenants have their stuff everywhere.

They will bring in shorter term tenants but the lease is still with the tenant the company just does the scouting etc.. still have to vette the tenant but you know the rent is coming from insurance and the rent for me is double market rates at least and generally 6 months to a year so not a ton of turn over and very good tenants..

Lots of posts here on BP on all the questions to ask as there are 100+ items to consider

It will familiarize you with the basic terminology and benefits.

If the appraisal deems it to be "Subject to" you will have to use a renovation loan/construction loan to repair and close. 

That way I know with less equity upside upon renewal or backfilling the higher cash flow helps make up for some of that with the overall return.  

Will you lose money on the clean? 

You may want to remove yourself from the situation since you are emotional about the situation.

The loan officer told me to come in the day after settlement to apply.

I'm under the impression that its ran similar to single family homes and like cap rates for the large multifamily.