Could the Glaive be retrofitted to use human parts?

I wouldn't expect anything like that in the near future. Vanduul weapons and their ships are very distinct to human ships. In the grand long term, won't rule it out completely, but for the near term and at least through getting all physically based damage out, Vanduul ships use Vanduul weapons.

And for the purpose of an effective aggressor craft, you want it using the weapons that you're going to be facing as a design point.