If you think about it like this,
Each character has 3 custom moves for each of the 4 move slots.
3 x 3 x 3 x 3 is 81 different combinations for each character, ( right? )
Multiply that by the roster size
81x 35 ( not miis ) is 2835 DIFFERENT characters. ( somebody should check my math that number seems huge )
If you add Mii's they also have a choice to be Small, Medium, or Large... So:
3 x 3 x 3 x 3 x 3 is 243 add that to 2835 and we get a whopping
3078 DIFFERENT characters.
Since special moves are split into fast normal and strong we can abbreviate these customization based in an order of moves of neut B side B up B and down B
for example there can be NNNN Mario's as well as FNSS mario or even a SSSS Mario. These tags could be put before a character name on tournament brackets in order for players to easily identify what special moves they have so they won't be blind sighted. Mii Fighters and palutena would replace FNS for 123 and mii fighters would look like this 1322 Mii(S,M,or L)(G,B,S) to reference size and mii type
As far as character locking goes I propose a certain player can choose a set 2 or three characters out of the cast of 3078 so they could have different base characters like a NSFF Mario and a FSSN luigi, or have multiple variants of the same character, I.e. a NNNN Mario and a FFFF Mario. consider that.
Also no equipment that ****'s dumb
also custom moves will most likely be tied to names just like control options. Just my guess tho.
It's basically just like conterpicking a character except there are about 3000 more characters than before

I think a good amount of pre-tourney selected characters would be 2 or 3 maybe even 4 though. you would choose between THESE two-four characters for each match.