It is pretty easy to make movement trays from thin PVC sheet, quarter-circle plastic dowels, and a small miter box. I used all that stuff to make custom movement trays for my Ogre Kingdoms army and it turned out great.
Why did you build him as a PC? If the point is to highlight legendary figures as potential NPCs, why not build him like an NPC as seen in the Monster Manual? It'd be far simpler and less restricted.
I do two things. One, being dropped to 0 HP more than once in a fight results in a failed death saving throw. Two, failed death saving throws do not disappear until after the encounter.
I ran a game once that had a lot of noobs (of the seven players who were at the table over time, only two had played before). The campaign went on for over a year but, somehow, most of them never really learned how to play D&D.
Getting them to explore the environment or follow plot hooks was...
Yup, Otherworldly Touch is trash. I would be leery of any homebrew on D&D Beyond since it has very little curation. Virtually anything can be thrown up there.
Also, their fluff seems kinda slapdash.
It is a very powerful story-altering ability, way more powerful than being able to walk out on your tab without consequence. It doesn't have much utility in combat, but that isn't really the point.
You are right that lifespan is essentially little more than background flavor, tho.
Why not simply eliminate the multi-shot ability of Eldritch Blast and make it scale like every other cantrip instead? That'd go a long way to pruning down its excess.
Strahd is meant to be faced at 9th level. If the PCs are higher than that, it is going to partially trivialize the final confrontation, especially if they are 11th level or higher.
That relies on taking someone's argument to an inevitable absurd extreme.
That is not the case here; they are instead refuting an argument, the argument that "physically similar" means "visually similar," that the other poster did not actually make.
Honestly, I think they might be trolling.