You don't have to trust any coinjoin coordinator you choose since no information is ever provided to them.
Except you do have to trust zkSNACKs not to censor you after they are done paying blockchain analysis companies to spy on you.
There are other blockchain implementations which do not have this weakness. Any sensible person will use one of them instead.
What "weakness"? What do you mean "blockchain implementation"? You are making no sense.
Rejected coins return to original address that's perfect if it's Bitcoin Core or Electrum wallets types.
Not quite: Rejected coins never leave their original addresses at all. No fees is paid, no coins are spent, no data is revealed. Being rejected from a coinjoin is completely harmless to the user, they can simply register with a different coordinator with absolutely no consequences whatsoever.
What happens next shouldn't include zkSNACKs or Coinfirm keeping tabs on my prior history UTXOs in Wasabi wallet or any future ones. As the receiver user I'd like to know will zkSNACKs or Coinfirm put eyes for following me or connect me to the naughty coins? It's important for understanding what Coinfirm does with data if they've analysed naughty coins.
zkSNACKs or Coinfirm cannot follow you or connect you to the naughty coins because your IP address is protected by Tor. They cannot connect the UTXO to any other coins in your wallet because your xpub address is protected by your client's use of block filters (
https://bips.xyz/158).
This is the most important difference between Wasabi and other clients like Samourai/Sparrow: Wasabi's developers and coordinators NEVER gain any data from you, whereas the Whirlpool coinjoin coordinator collects your data and will notify you when it gets turned over to the government:
https://samouraiwallet.com/canaryand what's Coinfirm doing with the info after they've decided coinjoin status?
We don't know, and Wasabi won't tell us. I suspect Kruw doesn't know this either - the knowledge is probably limited to the top 2 or 3 devs at Wasabi. But given that all blockchain analysis companies only exist to gather data and then sell and share that data with third parties, I would be
very surprised if Coinfirm don't use this data that Wasabi pay them to gather in a variety of other nefarious ways.
You do know because Wasabi is open source, just like Bitcoin itself. You can verify for yourself that no identifiable data is ever leaked by Wasabi clients to its developers or any coordinators. Wasabi is very proud about its zero data collection policy, yet you continually say that "you don't know" what data is collected.
The answer is
ZERO.