-I'd like to alter the character creation screen to only allow 1 or 2 characters for the party and not four.
Without having looked at the code, this should be doable.
-Is it possible to expand the item/weapon/armor names to 8+1 digits? 8 digits for name 1 digit for icon.
I believe this will be the easiest thing to do that you want. It's a matter of expanding the text (effortless, FFHackster has no limits on names for the equipment), tweaking a couple things in the equipment menus, and then just redoing all the text. By that I mean possible doing DTE for all the text with
this patch. I guess the description for that is wrong, it generally enables DTE in battles, not just for monster names.
-Expand the levels for the characters to 99 instead of 50? Is the EXP/level data hard coded or are there pointers?
You would need to add 49 more levels worth of experience, class level, and HP/MP growth tables. It would effectively double the size of that chunk of data. Definitely possible, but it would take a chunk of work, and you have the problem of it breaking FFHackster.