[Immobilier's fees.]

Like the original poster very well said though, the agency that is charging him the most commission is also briging more visitors. After you have some people interested if the price is high you can always ask the agency to move their commission down for the sale to go through. I mean even a greedy agent knows that 5% of something is better than 11.5% of nothing.

[How quick can it be?]

In Spain it takes 3 weeks for foreigners to marry. I.e. they have to be staying in Spain for 3 weeks as a requirement.