So bethesda has stated that in dawnguard if you transform into a vampire lord, losing your lycanthropy, you can get it back. What I want to know is if I transform into a werewolf, can I rebecome a vampire lord? Again, I know this is speculation, but what does everyone think? Vampire lord again or no?

This something you will have to find out on the release day, not too long now bro.

Probably not since im guessing its sort of like a ritual and not just a normal disease.

Much like becoming a lycan, it'll get rid of your vampirism and vice versa to be a vamp lord.
So probably not.

Probably not, and then, in true Bethesda style, you will be able to become one again in some future DLC.