Does a ghoul bloodline sorcerer count as a ghoul for purpose of the ghoul feats? Access to the Warren Digger feat would suggest it but I didn't if an official ruling was given.
RAW: no, it does not say you are a ghoul, so you are not a ghoul.
RAI: no, it wouldn't make sense to get a permanent burrow speed based on claws that you get for a minute per day, tops.
They don't get access to the warren digger feat. It's in a list of options, but Sorcerers need to meet feat pre-reqs. Warren Digger is there for ghouls with the bloodline.
(Another clue is that it's from the Monster Codex, which gives monsters options that some PCs can also use. That's why you've got a super-narrow feat in the list.)