I'll take your word on this and stand corrected.
On Choral Roll, I have no real idea how to change this to fit the theme of Bards. I understand where S-E was going originally since Bards aren't likely to get interrupted casting songs. This doesn't really fit as a roll, though, for the reasons I mentioned previously. Increasing resistance to Silence doesn't sound any more useful to me than Spell Interruption down. The only material change I can think of that fits the Bard theme is increased resistance to any enfeebling effect (let me know if there's a roll that does that already. I can't think of any right now).