Areas like Downtown, Summerville, and West Augusta are particularly desirable due to their proximity to amenities, universities, and employment centers.In terms of your preferred strategies, it would be helpful to know what type of lending you plan to use.

If the market is tough, I reduce the rent rate over the full 12-month term.

Historically, real estate will appreciate over the long term.  

New primary mortgage will be about $2500 a month, old house that I will rent out long term is $1000 a month.

I would at least recommend you have them shop a policy for you.One thing we did note is that with hail damage to roofs, they seem to be decreasing coverage/increasing deductibles on that if ever needed.

:)As for LTR rental terms, usually we sign a 1 year lease where tenants are expected to pay Electric and Gas if applicable, while the owner typically pays water/sewer/trash with the city. 

"We do not expect much further upside for housing demand near-term.""

If you ever see someone offering terms that are too good to be true, you might as well just post your SS# and banking information on IG.

Nonetheless, you can base the DSCR calculation on PadSplit rent (if there's a history of PadSplit income being produced) or short-mid-term market rent (an analysis done at the same time of appraisal).

I am a long term hold investor so that would likely be my play.Good luck Sean!