However, does the KYC process establish a permanent connection between your identity and ETH Wallet-address, meaning, that only one of us can now undergo the process of any new ICO as his name is permanenty linked to that wallet address and the KYC-procedure would therefore not allow the other person (as he is not linked to the wallet)?
Or is there no such linking and we can both apply for KYC using the same Wallet addresses.
Does anybody know and is able to shed some light?
Thanks in advance and best wishes
A company for which you undergo the KYC process can only link your identity to the provided address for their own purposes. If you choose to apply for another ICO (of another company) by another name (your brother's) but with the same address, then there shouldn't be any issues.
Understand this: sharing of customers' personal data between companies is prohibited by law in most countries. So, if you have any problems, you can sue them (and you should, they never should have played with your privacy and your trust in them!).