Cap1 wants at least 2 and sometimes insists on all 3. I've never heard of an approval with just 1.
Keep in mind they also check Innovis and Sagestream and/or IDA.
Not according to this language from Dan from a recent post
"Note that Capital One does a credit pull from all 3 credit bureaus when applying for cards, though some have had success getting a card with 1 pull by freezing the reports by 2 of the 3 credit bureaus. More info on freezing from Equifax, Experian, and TransUnion."