I tested the dice rolls on three different seed generators and they all had the same seeds generated... so that was my verification. Still not good enough?
Major downside is this wouldn't be reproducible on other wallets as a way to verify the math as up... Like inputting the dice rolls can be verified on several different seed generator projects.
Xor is a standard computational algorithm. I don't think there's any entropy in doing an xor. It's more like doing basic addition and subtraction. Maybe some one else can chime in if I'm wrong about that
I don't think there's such a thing. If you used dice rolls it does not use the built in random generator at all. It uses a standard algorithm that all the other seed generators use too (the seed words you get are reproducible given the same dice rolls). If you used the dice rolls then used the password generator to make a passphrase you should still be ok as the important part is the seeds and those used the dice rolls as the entropy. But you still may want to change the passphrase and move the funds.
I verified dice rolls as not being compromised by inputting them into three different seed generators (including the cold card) and they all generated the same seed so... not compromised.