Removing the old paint “edges”

I have cleared directly over (after full cure and scuff as mentioned prior) Acrylic Enamel with great and long lasting success but I don’t know how those products work in the real world so... Your answers about the paint are already above but I will give my 2 cents on stripping it off.

As mentioned above, I would blast it myself or have it blasted.
Most of what I use is either Soda or plastic media. (Won’t warp but take special equipment)
Recently I have had a couple of cars done with No-Dust mobile blasting. (They come to you!) It’s really the best of the best aside from having the entire car dipped which I really prefer for a full restoration. (by a reputable shop that can dip enter car)
DIY is definitely cheapest, I don’t blast large flat areas with sand style media unless there is pitting, those areas definitely get blasted (you will warp flat non braced sheetmetal very quickly and easily) although I definitely do blast the back sides of the doors, fenders, trunk, jambs, engine comp etc etc....
Then after it is VERY CLEAN get a good coat of etching primer (like PPG’s DP line) on it and that will be your perfect base to start with and work on top of.

Just be careful and take your time and start by testing in places that won’t matter too much, (or on junk!) adjust your pressure and flow rate and keep pressure under 100psi. (I run 65-85psi with high volume depending on media)

Good luck!