Obviously, our combined income could obtain us a decent loan with a down payment on a house, but for multiple properties, I am not sure how well we would fare.

A licensed mechanical contractor should beconsulted for repairs THIS SHOULD RESULT IN A LOT OF WATER ON THAT FLOOR Could not test Air Conditioner as it was too cold outside TRANE UNIT, 2010 A white powdery deposit was observed on two brass valves at the rear of the crawlspace, which is indicative of deterioration of the brass alloy and may result in leaks/failure at the valves.

Neither is innocent and I’ve told them both multiple times that they need to act like adults and be respectful of the other (music and noise to a minimum during the day and nothing at night as stated in the leases.)

Multiple offers on day 1 Lessons learned?

Here's an easy test/rule...50% rule. 

It is a big management company that has multiple buildings in more than 5 major cities in the U.S.

They can also suggest segments that won't be getting multiple offers every month.

They have programs to put multiple properties under one loan

California now has a pretty onerous brightline test of sorts after the Dynamex case last year in the CA supreme court.A hired worker will be considered to be an employee unless it can be shown the worker passes ALL of the following test:1) The worker is free from the directions and control of the hirer in connection with the performance of the work, both under the contract for the work and in fact;2) The worker performs work that is outside the usual course of the hiring entity's business; and 3) The worker is customarily engaged in an independently established trade, occupation, or business of the same nature as the worked performed for the hiring entity.Note this is a lot more restrictive than the federal "questionnaire" for an employee vs IC determination. 

I've partnered with a multiple good friends for years with no issues.