Charlaquin
Goblin Queen (She/Her/Hers)
I’m pretty sure the intention of the question is to gauge whether the wording of the options, or any rule elsewhere, precludes what they’re asking.
I mean... You might as well ask whether there are any rules preventing you from combining the SCAG variant half-elf rules with your own homebrew half-drow subrace. The answer is, the subraces in question don't exist in the rules of D&D 5th edition. There are no rules allowing or disallowing it. If you want to use them together, knock yourself out. If you don't want to allow it, that's also legit.