Yes and yes. There is a HAZ (Heat Affected Zone) with plasma cutting just like there is when welding stainless. With an AVIDcnc and a correctly functioning THC and correctly programmed travel speed, the HAZ is super small. Where MIG/TIG welding one might expect 3/16~1/4in (depending on material thickness, travel speed and heat input) it is pretty common with the plasma cutter to have 0.050 or less. Since this is air plasma cutting, there will be surface discoloration that will needed to be ground/sanded back if a cosmetic finish is needed. I’ve done several signs with thinner material and simply hitting the surface lightly with an angle grinder (flap wheel or paint stripping wheel) was more than enough to clean it up. There are a few examples of that shared here in the projects pages of this forum.
You can zee the HAZ in the photo 3 & 4 of this Project
Also visible in the closeup photo of the ghost in this https://forum.avidcnc.com/t/a-fun-halloween-project-from-back-in-2020/2049
I’ve done a few other projects in stainless (mostly thinner stuff, I’ve only recently started cutting thicker stainless on the AVIDcnc) and edge quality seems to be pretty consistently the same as these.