If you're going to go that way, the obvious word to add would be ov, a more "cult" spelling of the word "of"

instead of "za" I would suggest "ze" as a pronoun for a non-binary person

I assume 'ye' and an alternative to 'the' would be acceptable under those rules then?

I think it's already accepted as in "Hear ye"

What do you suggest as a substitute insufferable way of referring to pizza?

I already said, no more za, add "ze" as in a non-binary person

Part of what I liked about older scrabble dictionaries (you can use any dictionary you like) was the variance in difficulty in using various letters. Get an 'X'. That is a nice letter to have with high scoring potential with lots of two letter words. A 'J', not so much with only JO as a two letter word. Z, high value with a large word set, but can't go two ways (no ZA). Q, high value but a bit of a pain in the ass and you need a U. Maybe you should turn it in. Now with QI, QAT, etc., the Q is not as cool. But nothing says you have to accept those words. Often we don't play with them.

As suggested elsewhere, we play with a two letter cheat sheet to make the game more fun for those that don't know all those words.