Not a programmer but that seems odd that they cannot be imported. The number of posts which is an integer associated with my name was imported but the number of likes which was another integer associated to my name could not be imported. Seems pretty simple. If you have to have a new counter newlikes then just redefine it to be newlikes+ oldlikes. where oldlikes is looked up from a table.
Likes were not part of the native vBulletin system. They were an addon. Likes in Xenforo is part of the native system. They don't mesh.
It's like a New Year's resolution. Clean slate.