Carpet also holds odors which can be a real turn-off for prospective tenants as well.Figure out who your target tenant is and then install the flooring they want.

Remember, with pet odors replace what you can, but oil-based Kilz is your friend.   

Wall wash with TSP prior to painting if possible,, if the ceilings are flat (not popcorn) wash also, a sponge mop with a towel over it works great and fast..2 buckets one wash one rinse.you wash everything,, doors, trim, floors, cabinets, light fixtures, all windows glass and tracks.Bleach is ok to use but I've found that TSP is best thing to actually REMOVE the nicotine,, you'll be shocked when you see how well it works. 2 Prime, Kilz primer to seal anything your going to paint.3 Remove all blinds, throw them away the plastic retains the odor and they'll be gross anyway.4 Air Ducts if you can reach inside wash out.. then spray Kilz in them as far as you can reach with the system off.  

Leave it unvented (okay by code for electric stove) and hope to avoid lingering odors and yellowing of walls2.  

Odors tend to transfer to the pad overtime as well so the best course is to rip out the pad (remove the carpet in a way so you can reuse it), replace pad, retack carpet and the next day get the carpet professionally shampooed. 

Did the carpet guy write up something that says there was pet odor in the carpet and needed the deodorizer?

If they get the slightest bit wet they will discolor and look awful, and if there is ever a humidity issue those tiles will hold a musty odor forever.

Renting to students is a good model, and unlikely to run foul of the Portuguese tenant-friendly laws for renewals. 

Also, they do have a odor-free guarantee as part of their contract.I'll let you know how things turn out in the end.

Why can't you say "My role is to find you a buyer who can pay cash and do it as quickly "  Give m"e 'x' days and if I can't do it then no harm, no foul"  If there is a drop dead date then don't take on those contracts if you cannot buy it yourself?