If a garantia is required by the owner I will use one of the garantia companies that supplies one for a couple of hundred dollars, or I will pay the owner a few extra months upfront, the BS with the garantia or someone owning property co-signing for every lease is a myth, show the owner some US dollars and the garantia will not be required.
yes, do that. because the garantias you can buy can be detected. Inmobiliarias (real state) do it, it's part of their job (of course there are also some inmobiliarias that want their comission, and offer you the garantia, something from what the owner has no notice).
Better offer to owner to sign a contract for a shorter period pay a period in advance, and an amount as warranty. Or it could be 2 months + 1 month as warranty, and renovating each time. The owner will feel more confident (and happy to receive an interesting amount all together).
BTW, are you looking something quiet, simple, or with amenities? because I have a co-worker who lives in San Isidro and has a place to rent.