We are selling some property on Land contract and I would like to use a loan servicing company to collect the monthly payment, and setup escrow for taxes/insurance.

It's a math problem more than a qualification problem, but you may want to cap your loan amount to get a better rate (and cash flow) vs maxing out and having a little more cash, but really bad cash flow.

The 10% down second home loans are much more difficult to get now.You will likely need a 20% down investment property loan.Yes you can do a cost seg study for this property.I'd be more wary about finding a property that can cash flow and be allowed as a STR than tax breaks.

I discovered a guideline that prevents lenders to loan to Condos that have master homeowner's deductible > 5%. 

Due to the rising cost of financing, the deal fetched an 8% cap rate, typical for transactions in this size range.As we move through the first quarter of 2024, the $180 billion in retail loans maturing between 2024 and 2026 presents a significant consideration for the market.

During that period, the number of closings fell for seven consecutive quarters before rebounding 74% over the ensuing two years.Additionally, the $24 billion in maturing CMBS loans this year could stimulate sales activity as the interest rate environment will likely be much different from their rates at origination.

If there is a loan involved, you must have the mortgage companies' permission to transfer ownership.

You know the seller's asking price and loan terms (is it interest only or amortizing?).

As you pay down loans and increase rents suddenly you’re making more and more money and those suspended loses go away.

I think you may be referring to Land Contracts, which is where the title of the property remains in the seller's name until the loan is paid off.