Depending on the lender's protocols, either traditional or virtual appraisal methods may be employed.

Since I will be leaving my corporate job and effectively self-employed as I manage most of my MF portfolio, can I roll my retirement savings into a Solo 401k and invest in RE with the money?

You establish a employee-employer piece work job or per hour, 3. 1099 does not work, Yup!

I’m self-employed, so most likely won’t be approved conventionally. 

I'm looking for possibly an internship or an employment opportunity, I'm knew to the business however I am quite informed I just need a little direction.

If so, you have options that don't require income and employment history like traditional financing does.

If he were employed by a company, you might be able to get wage garnishment, but that will be harder if he is an independent contractor.3) If you have a judgement, yes, but keep in mind the collection agencies usually keep 50% of collections.

Are you self employed ?

You would have to maintain the self employment activity and not have any employees other than a spouse. 

Such short term rental  will follow these criteria(see numbered list below), in order to take advantage of (1) qualifying to fill out schedule E, thus avoiding the Self-Employment tax should there be any profits. and (2) being able to offset your W2 income should there be a paper loss.