I think 1 of them definitely is. Because, it has that weird notching that only seems to fit in a Yankee. The rest (save for one brad tip drill bit) are the same kind of cut in different sizes, but they all have a smooth butt that wouldn't fit well in the Yankee's I have seen (it would just sit in there and easily fall out). Moreover, being round like that I can't see them not slipping under any amount of necessary torque unless the inside of the bite holding them was that right angle triangle shape that holds pipes so well. Something this drill does not have.
I am almost certain none of them went with it originally, now. Because, they all fit in length wise with way to much room to spare. So, much room that after dropping them down it it's hard to get them back out...I would like to know the name of that specific kind of bit though. It's not quite a routing bit, but it bares similarity. could be a dowel bit if it had grooves ( which it doesn't)? In any case he will end up filling it with what ever bits she does, lol.