Most larger windows are an odd (old) size and solid pane and do not open.

The reason I say this is that no matter what your remodel if you are doing a lot of the work yourself (way to max out equity growth) then maybe look for an even larger remodel than you had thought about? 

Your rental pool is larger with smaller rents than with a SFH.  

Umbrella insurance is usually a very large policy of $1 million or more, extending your coverage for larger situations.

There are a lot of things that can come up on a flip so easing your way into things and working your way up to larger rehab budgets, etc is recommend.

Also, liquidity. 

A hard money lender typically will go from one loan, to three, then three plus depending on quality of the flips and your liquidity. 

With Tiny Homes, a person can get all the upgrades that want like that in a larger home.

I am hoping this gives me a head start in funding the initial investments.I also have some high balance liquid assets, but I am putting all or most those funds into other investment vehicles to diversify my holdings such as stocks, bonds, etc.

You can build equity by leveraging a larger property if you don't need the monthly cash flow.