Hi, having dealt with long term rentals in the past, dont get pushed into paying a finders fee to any agent, almost all NOW get their fee from the owner upon finding a tenant. If they are managing the property their deal is with the owner and not you.
It used to be the practice that agents obtained a finders fee from the tenant and some still do, anything from 50-100% of the rent – up to you if you find something you fall in love with and decide to pay it.
1 or 2 months deposit and 1 month rent payable in advance, if you find somewhere (and I would strongly suggest furnished until you decide to relocate permanently) place a small holding fee and then the remainder as you collect the keys.
Any spanish bank will set up a direct debit to pay the owner so dont worry which bank you go for.
Do not get involved in paying community fees, this is the owners responsibiliey, you pay electric and water unless you have an all inclusive deal but they are rare.
Sign a short term agreement initially then extend to an 11 month – I would suggest you sign an 11 month with the option to finish after 3 with a 1 month notice from your end, then you should be fine and flexible.
Tenants deciding bot to complete the contract can sometimes give a 1 month notice and then move if its written into the contract.
Finally, good luck with it and enjoy your new home, I hope it all works out for you.