👺Can't Chop Cheat?

If ChopChop is providing the seed, can't Chop cheat and do the calculations ahead of time?

No. The seed is just one part of the calculation. There's no way for ChopChop to know the block number and block time that the winning game will be mined on/at. It's the same in reverse. Since you don't know the seed, even if you were to find some way to collaborate with a significant number of block miners, you would have a very hard time guessing the correct winning number.