Since you're an individual, mainly whether or not the 4plex was built in the last 15 years.Assuming the tenants have occupied their units for over a year you'll want to give a 60 day notice.Alternative route?

Self Sufficiency test is the important item for 3-4 unit FHA homes. 

My builder has 4 houses in the area already built and on MLS but I can't deploy another owner occupied mortgage for another 11 months.  

You should negotiate with the landlord that you don't mind taking care of small repair items such as tighten screws, drywall and paint repairs.

In my opinion, if what you want is leads, you aren't going to make the right use out of Pro because you will be trolling for buyers and sellers instead of being an asset to the community and answering questions.If you've been a Pro member for several years and have only made three posts, you haven't been interacting with the community over that timeframe and that is where relationships are built.

Depending on the built in gain and how long you've lived there, you should be able to sell your current primary tax-free and roll any gains from that into your new primary residence, that is IRC section 121.Is there a set amount of time before you can move into the rental as your primary?

well 70% of 455ks isnt much more than you currently owe at 283k the 70% of 455k is 318.5k and after closing items you might only net 20-30k tops (new loan minus current 283k - closing items = net proceeds in "hand.").So The question you should be thinking about is what are my closing items and is this enough cash to accomplish my mission/goal?

It also a property management piece built in with lease management functionality and maintenance requests. 

Don't think it's worth it for 1 property.Vrbo and Airbnb will sync calendars with each other and send basic messages already.Vrbo has free built in pricing tool.

Tenants start a maintenance work order, then want someone to come on a Sunday at 7pm for the service call.Warranty companies are also notorious for built-in system delays.- How do you think they make money?