In two months you can only clean up, paint and carpet, maybe a few other easy things (there is always something!). 

Renovation PlanScope of Work:Convert 0.5 Bath to Full BathEstimated Cost: $7,500Details: Add shower or bathtub, update fixtures, ensure proper plumbing.Add Bedroom in BasementEstimated Cost: $15,000Details: Install egress window, insulate, add walls, flooring, and electrical work.Replace DeckEstimated Cost: $3,000Details: Replace existing 8'x10' deck with new one.General UpdatesEstimated Cost: $45,000Details: Update kitchen, bathrooms, flooring, paint, fixtures, and necessary repairs.Total Renovation Costs: $70,5004.

NOT a big deal, Scrap and paint the windows or better yet just replace them.

We updated the unit cosmetically through paint and furnishings, as well as consolidated the kitchen and added more living room space.

My (non lawyer) read of the SC rules paints a much different picture in those jurisdictions than what you discuss in TX - where it sounds like you own effectively nothing but a tax note until the close of the redemption period - you can't take possession and rent the property, real estate taxes during the period are still the responsibility of the original owner, etc.The below is from the County of Charleston SC's website regarding the tax sale and how they work in that particular jurisdiction - certainly not the authoritative source of their state statutes, but for posting on a forum, I'll take it for now. 

Complete remodel including new flooring and paint throughoutupdated the bathroomremodeled the kitchen- added a dishwasher and gave more dining room space (did not remove a wall just remodel the kitchen so that the refrigerator could fit in it) added more cabinet spacenew light fixtures throughoutadded curb appeal What was the outcome?

Remodel a kitchen/bath/new paint/maybe some new LVP flooring?

More likely to fix holes and paint than replace a used appliance.  

Floor is just painted concrete, and that includes the 300sf which the county assessor counts as fully finished.I'm reading that DSCR rent appraisers may not count partially finished space at all, and count fully finished basement space at only 25% of the rent of main floor space in the same house.What are your thoughts--is this how it typically is for DSCR rent appraisals?

That often requires replacing or updating some items like outlets, faucets, have furnace cleaned, clean AC coils, new appliances, paint the property, etc.