I think the real question here is: If you are Sephardi but look Ashkenazi, can you do something that Sephardim are allowed to do or would it be considered “maris ayin” (the appearance of doing an aveirah even though you’re not).
I can’t imagine it’s a problem since there is no such thing really as “looking Ashkenazi”. There are plenty of Sephardim with light skin and I think people realize that.
However, I could see there being a problem if you follow the Ashkenazi minhagim for some things. I don’t know if it is a problem – you’d have to ask your LOR – but that’s the only situation in which I could see a problem.
But even if that’s the case, in our situation in which you are doing something that is even fine for Ashkenazim, I can’t imagine there’s a problem.