I've played both the Celestial Tomelock and the Arcana Cleric Magic Initiate and really enjoyed them both.

The Wood Elf Battlemaster is going on my "to play" list. Great write up! The one thing I'll likely change is the order of the ASI's. I'll start with a 17 Dex and pick up Elven Accuracy first as suggested, but then follow that up with Ritual Caster at level 6 for Find Familiar. The plan is to use the Owl for a help action on the first attack, triggering the Elven Accuracy for a Trip Attack. If the Trip works, then I'll have Elven Accuracy for the second attack as well, while helping any other melee types in the party.