I'm not putting a cap on recruitment at this time.
20 base HD is somewhat worrisome, yes.
How about this. Shave its HD to 15, and we can forgo the Young template, though you can also use it if you want to scale down the Neothelid. Also keep in mind that being Gargantuan (or even Huge, if you use the Young template) is likely to cause you obstacles at some points.
Advanced Races Guide races are automatically allowed, no approval required, but but in case you hadn't guessed by the presence of a half-dragon, a half-giant, a handmaiden devil, and a succubus, I'm fairly lenient. If serious problems come up in play that negatively impact the enjoyment of other players, I'll step in, even if I approved something before, though, so please be considerate of your fellows.