I think he does have a lease with the tenants, but he said the realtor contract is only for the realtor to lock in the client for a specific period.

I knew a couple of “we buy ugly houses” franchisees that purchased and fixed about 50 homes per year and wholesaled another 75 - 100.  

Looking to purchase max $800k ideally around 600k

I have purchased an apartment building (with 9 units) in an auction deal.

Unless you already have buy & hold investors lined up make sure you have a reasonable inspection period as showing occupied properties can be a real pain unless your buyers only care about the rent & purchase price.

Purchase price?

I'm uncertain whether to wait until we settle down before starting our real estate investment journey or to purchase a home at our next location and rent it out when we move again.

Tax sales are a balancing act among (1) the need of government to collect property taxes and, if owners will not pay then, then to provide incentives for investors to purchase the tax rights and (2) investors, who need an attractive return for the risk they are taking, and (3) citizen taxpayers, who should not lose their property and all equity because of small debts and perhaps temporary or at least relatively short term financial difficulties.

However, there's no AC and heat there and I have already purchased min splits air conditioners and an electrician has also laid the lines for me.

In my market, agents/investors/wholesalers pitching creative financing get this objection as well.They typically have a 2nd offer (usually much lower purchase price) for the owner to be able to accept now and cash out.