Closing costs on top of that were very minimal...1% transfer tax, tax reimbursements and some other small misc fees.  

That's about as low tech as you can get + minimal security. 

We used our own money to build it - I am also a GC so the costs were relatively minimal.

Are there other options to consider or explore to minimize costs for both parties on all fronts including taxes?

Is there a limit to how much one can increase rent in Colorado with a 30 day notice, what recommendations can you all give me on how to get them out quick and with minimal costs?

How can we minimize tax liability when pulling these funds and using for the house?

I'm eager to get started, and I've already determined I want to do BRRRR (which as I understand, if I play my cards right, should cost me no out of pocket money).Should I just focus on minimizing expenses as much as I can to get that safety net quicker?

If you are doing a full rehab maintenance should be minimal.

I suggest a grass variety that needs minimal watering and mowing, since this would appeal to tenants with pets as well. 

The management hours are minimal, about 1.5 hours per month per property for the bookkeeping, scheduling repairs, etc.