I like some of the ideas (Jean and Paul, Alina, Timotheus, Astrid & Inge, Alis and Marie, Isabeau). These are easy to integrate. Big Eye is a bit borderline, but she might work (the villagers of Chastellion might be the ones who call on her services).
Others sound more like companion ideas than grogs or covenfolk, because they have story potential but would need a player to want to play them (Spyro, Linda, Claude, Andrea).
There are several that just don't fit well into the background of the covenant. This isn't a place that was really a covenant until now, which would mean Florian wouldn't fit. The Doctor couldn't act as if he's a magus, because this wasn't a covenant before.
We also aren't looking to add story hooks for the covenant (see the covenant's Boons and Hooks), so a number of the ideas would need to be toned down (the heretics, Andrea the turb captain, Paul the spy).
And Wilhelm couldn't possibly be alive, since Leonardus himself was well over a hundred years old when he succumbed to Twilight. The idea (and that of Florian) could be modified for any former trusted mundane (purser, scribe, cook or maybe the glassworker) who is now too old or crippled physically (arthritic, blind, lame).