hey Coco, if you find the perfect place for you and the landlord is iffy (for whatever reason), you can offer to sign on for 2 years but they will not want that.
most will want a basic 1 year contract since they do not know how you will work out as tennants either.
if you have the euros and are really in love with a place, you can offer to pay 6 months or a year in advance.
all in all, don't offer too much as you will look desperate and the landlord may think you have some hidden agenda.
odds are you will find a place you like so when you do, just ask the landlord the conditions of rental and do not start offering your first born at the start. ask the landlord what they require and if it is reasonable (1 month security deposit, aval, nómina) and you can provide for it, you will be fine.
as for yellow, i love the color (one of my faves), in fact, ena and i are about to pain our living room pastel yellow. call me ignorant but what does yellow have to do with the heat?

as for painting the place you take, ASK THE LANDLORD IF YOU CAN PAINT BEFORE YOU SIGN THE CONTRACT.
saludos,
jer...