2) We do have my brother-in-law in Barcelona so we could transfer the money to him and then have him do the transaction with the owners in person. Not sure how it works in Spain, how much faith people have in their banks compared to here -- I know a few members on the board have lived there and/or still do so hopefully they can help out
You should check this with Spain. Money laundering policies have been growing in the EU, and I am not sure you can really move money around like this.
I believe that if you want to buy a house from Mr X, the money cannot come from Mr. Y account, and it could put Mr. Y in a bad spot (he might have to declare these money and pay taxes on them).
I don't think that you can handle 70k€ cash, nor deposit that amount in cash at the bank.
I am not from Spain, but in Italy things have become pretty strict as far as cash goes. I don't know if it is some EU regulation enforced locally, or if it is just an Italian thing (Italy is not exactly the sheer image of legitimacy and these things usually happens because they are imposed by the EU)
For example: in Italy, the limit for cash transaction is a mere 1k€. This means that: you cannot buy something for over €1000 and pay cash, you cannot withdraw more than €1000 cash without filling in a written form, you cannot exchange money for more than €1000 without filling in a written form. If you need to withdraw more than €5000 from your own bank account, you have to fill in a request form.
Now they are talking about declaring even money handed over by relatives - for example parents giving the son some k€ --> the son should report it.
These are some examples of how absurd things have become. Europe is not easy going like the US/CA.
I visited Spain recently and I wanted to open a bank account there, and I was somewhat laughed off because they told me "You cannot simply walk in here and open an account" (which is exactly what I did in the US, btw!). They said "You have to justify where the money is from (I showed them my tax returns), you have to explain why 'in Spain', you need a letter of reference from your bank, then we will hand over your request to our international acct. dept. and they will give you an answer"
It is so f****ing complicate!