You probably don't need to start forming any LLCs until you actually have some property, but it is best to form a separate LLC for each property and then form a separate LLC for your holding company.

You may want to run the different scenarios by a CPA first, but I think if you file your taxes as married filing separately then you can apply the gains on your return.

It will separate your transactions for each calendar year and continue downloading data as directed for 3 years after your purchase so a single software purchase should hold you over for a couple of years before you might need to upgrade to a new version.

I would keep that separate from the business.  

Is that acceptable given everything is separately metered and renters pay for all utilities?

I always try to give myself as little exposure as possible, and also keep all ventures separate.

Yes, i could flat fee list it, but having done a separate deal recently in which things went sideways prior to closing, i'm reminded of how important it is to have a great agent on your side (and how important it is to pay your agent appropriately).

To further diversify your risk, you can put groups of properties into separate LLCs. 

I can use a lease option contract which states rental rate, option fee, basic terms OR have a rental agreement & separate purchase option agreement.

I have seen many others on BP argue for a separate cap ex line of 10% in addition to the 10% on maintenance.