Sorry for double posting, though I feel the need of telling more details of how to appropriately help out a Pokémon with a new typing combination.
- "Is their stats good enough to serve its new typing?"
A bad defensive typing can be detrimental if the Pokémon's stats lean to defensive styles, and a Pokémon with paltry BST will perform poorly in OU no matter what (Shedinja is more situational but still not optimized enough to be OU viable). Fix the latter case by increasing their stats to more functionable level when possible, but don't go crazy with it.
- "Do it have enough tools or utilities to function properly in their intended role(s)?"
A wallbreaker would be limited if only accessed by weak or average moves and no strong moves, and a wall cannot stay for long if lacking any way of recovery, so check out the Pokémon you want to retype first to see if they got the appropriate Moves or Abilities to work well.
- "When I buff the stats, shall I keep it faithful to the original stat distribution, or should I give it a new role if its typing prevent to function well?"
The latter should only be done if 1) the Pokémon's BST is already low (below 500) and 2) if the staying faithful the original stat distribution would not help if the new typing would harm its role. Otherwise it is a good idea to stay faithful to the original stat distribution.
- "Should I make a move/ability/items based of an existing move, or should I do something more unusual, unique or not often explored, but still viable?"
It is up to you, and the comminity will decide if the ideas will worth to be in Typing: The Mod.
- "Would it be bad if I give stat buffs to any Pokémon with BST at 500 or higher?"
I would recommend to only put a slight buff of 5 to 15 to a few stats, and only if the Pokémon is not OU tier and not ranked B- or higher. For example, if Infernape will be retyped and that you want to buff its stats, put up at around +5 in Attack, Special Attack and Speed, and don't go crazy about it.
You should keep these questions in mind at the next Type slate. If you have any objections, reply when needed.