A lot of this process depends on your laws regarding STR and Mid term leases/occupancy?

The sky’s the limit, however, depending on the sophistication and the amount of due diligence help you request. 

On an annual basis, the administration is mostly meeting minutes, resolutions, and annual filing of your 990, most of which can be outsourced depending on your budget.

If you are thinking out of state, it really depends.

And this does not include the real world issues, namely are you even allowed to convert this property to a four-unit and taking a single family to 4 unit is very likely going to cost more than $110k (but this depends on the actual layout and work scope).

If they are able to remove the term it will be dependent on the loan underwriting requirements, not because they want to keep you as a banking customer.

You can request a look-ahead schedule from your GC or as Chris stated, create your own to keep track of resources, delays, and other tasks.

If you have less than 20-30 rentals Quickbooks little brother Quicken is much cheaper, easier, and still overkill for such a simple task.

As for cash or not I think it depends on rates, your level of risk tolerance, and what the opportunity costs is for that money. 

Depending on your state you may or may not be allowed to accept a partial payment during the process.