Mm...I'm using a different font in mine so it looks like 1 more letter could fit perfectly in.
Fixed width still. No matter.
Regarding SRAM, you'll want to find 7 free bytes (one for each character) so each name will fit 6. Afterwards, you'll need to hack the character naming screen to allow for the sixth position, then hack the routines that accept names to allow the new letter. Beyond that, you need to find the routine(s) that grab and display your character name, and hack that/them so the last letter is also grabbed for display.
It's not too hard, just tedious.