Not any offense meant to the poster of that recipe, as recipes vary wildly all the time, but I have never seen or made Bavarian Cream with gelatin. I rely on egg yolks for the thickening and always add 2 extra to mine as I prefer it really thick, but not set the way I can see it happening with gelatin.
It does not make that recipe wrong of course, just new to me.
If you did a small bowl of gelatin with milk, let it bloom, then warm to dissolve and add in, it might work. I would be more inclined to make a very small very thick custard batch and fold it in once cool to thicken it, but that is only my unfamiliarity with gelatin in this talking!
@ Yvette--If the customer wants Bavarian cream, go for it! Good stuff!