Air conditioned air leaking to crawlspace making crawlspace heat or cold depending on season causing more power bill to tenants.

Depending on market, I would plan to invest 100k in a single family home, find a good property manager, realtor, attorney in compelling market and just start. 

It depends on your local laws.

Snow removal is typically dependent on the amount of snow.  

I also know Arizona is fairly investor 'friendly' and has fairly low property taxes.Interested in purchasing small multifamily properties (2-8 units) depending on the property and numbers of course.

It really depends on your market and the owner's needs if sub to is even possible.

It might be worth quite a bit, depending on how much cash flow it is generating.

Homes prices are still at record highs, some decreases-depending on the city, however, high density apartments are skyrocketing.

The process is very involved as you'll have to navigate pre-construction activities that involve architectural plans and approval from the city and then the construction activities (Shovel to soil) take anywhere from 5-9 months depending on how much your building. 

Depending on if you qualify for the special allowance for active RE, you may be able to take up to $25k in losses (unless you are full time in real estate and may be able to use real estate professional status).