You should only be liable for tax on any appreciation since you inherited the rental (minus the cost of your improvements). 

Register for the free BP webinar that Brandon Turner hosts each week. 

10k Course, Sub 2 an inner city boarding house, Cost Seg, Cook Islands Trust  Naa, you forgot a step: after the sub2 and before the cost seg you need a G6

If it's a roth IRA, you may be able to take out the principle tax/penalty free.

Also, I found 2 ideologies regarding such development projects: Use one GC for the entire development or use that GC only for crucial trades such as foundation, framing, roofing , external siding, etc. and use sub contractors for finish and interior work to reduce cost.

If you have any more questions, I'd be happy to go through more so feel free to DM me.

Whether to build on your lots now or wait depends on a few things: construction costs, rental demand, and your financing options.

Feel free to reach out if you have any questions/to discuss further.

If you want to discuss bookkeeping options further, feel free to reach out!

There's no real hard and fast way or only 1 way or doing your first 2 points. your subject line suggests you're not looking to go to a large shop like a JLL or a CBRE which honestly I don't blame you those offices are usually pretty bloated.As far as monthly costs, if you are going to individually get a costar or other such license you are probably looking at $500-$1000 a month pretty easy in overhead once you have office dues, mls dues, marketing, etc.