In my linux/windows miners, 0.3.4b version has 'DevFee Accepted/Rejected share' message even with "--fee 0" argument passed.

Code analysis says the same. That's the part of windows version which processes --fee option. When it set to 0, variable gets assigned to some non-zero value, which influence program's behavior later:
 

No. Even with --fee 0.0 it still spends about 5% of time mining on developer's pool. You can check them by 'DevFee' string in the log.

Version of EWBF's zec-miner without developer's fee.

Thread which used to mine for developer's fee now works on your shares, so,
you can notice 'Accepted share' message with wrong share counter in program's output. That's fine.

Address for donations t1PD6bM1L7A3MdDJHvsmKwaD2a96vpRxS6P

Win64: https://mega.nz/#!Q34kQLyb!vekU930d5k6wYgMUYjyhPJtdpQR6kp1mZae0IhncRmg
Linux 64: https://mega.nz/#!4iIClQ4D!tbff8HgrT5Pii8yMDXf9eZd5yFSrwOALHnjsaW7NlWU