I tried to tell ya those things don't get the plan... but did ya listen? Nooooooooooooo.
For the spalling and other repairs, I used an epoxy product to repair the floor. I think it was Rustoleum epoxy shield floor patch.
After you use the floor grinder that is right for the job, don't bother with acid etching. You're effectively doing with the grinder what the acid etch does which is open the pores to allow the epoxy to soak in somewhat and bond. If you feel you must use acid, rinse with a baking soda/water rinse to neutralize the acid. I'd just clean up the dust, rinse the floor down well and let it dry. Once dry, place a piece of plastic taped down on the floor to make sure you don't have moisture trapped in the concrete. After 12 hours, remove the plastic and see if water vapor is present. If it is, get a big home dehumidifier and let it run for a day to pull out the moisture.
The important thing here is floor temp as well as ambient air temp. If the floor temp is too low, you won't get a good cure before you topcoat with clear.
OH! And for the heater, I'd go electric. Moisture is a byproduct of combustion. Any ventless gas heater will add moisture. I think can rent those 220v hanging heaters (the ones that are small squares like 16"x16") at a lot of rental places. If you do go propane or gas, run a dehumidifier at the same time. The nice thing is, the dehumidifier will put off some heat as well to help heat the space.