What payment processing charges? My bank doesn't charge me anything to pay a bill. Do you mean that the landlord has to pay to receive the money?
Only if you pay by credit card but I dont know if they allow that
Depends on how they recieve it.
What seems to often happen in cases like my town is that they've farmed out online payment to some third party processor. I'm guessing they do this for free or a reduced charge in exchange for a fairly hefty processing fee. As a result, it's cheaper for me to pay town bills via check even if they're usually online check via my bank.
Never seen a charge for a wire transfer in europe.