House Hacking is how we started - and did a lot of the updates ourselves in both units (new flooring, tile, etc). 

Ask how many units they manage and how much experience they have.

But a good place to start is by figuring out what a rough price per square foot cost would be in your area for a unit turn, cosmetic, and full gut renovation.Here in Chicago unit turn might run $15-25/SF, Cosemtic $45-65. and full renovation $90-$110 of interior renovations only.Hopefully this at least steers you in the right direction.

I am also interested in buying single family or multi family (4 units) for long term rental this year in the Houston area.

We engage in variety of strategies/tactics, including wholesaling, flipping and rentals (long/short-term) for acquisition of  single and multi-family properties, and small apartment units (5 -50 doors). 

I have a 16 unit I'm renovating and looking at installing vinyl plank definitely in the downstairs units, but unsure about upstairs units due to noise.

This is GOLD!

This amounts to lost opportunity because if you had purchased RE, at the closing it can start producing return. 4) ADUs detract from the existing structure whether this is privacy, a garage, or just yard space. 5) this is related to the value added by the ADU, but there are many more buyers looking to purchase homes for their family than there are RE investors looking to purchase small unit count properties.

I've been toying with the idea of scrapping the building and starting fresh, creating a six-story building with at least six units, one per floor to rent out.

They may show units too.