I just have a hard time believing they would sell him in the winter window - normally you never get value in the winter window anyway. But while the Basque club need to finish the season strong, they will not be crippled by the loss of Laporte - their cantera is loaded, especially with defenders. Getting the most money they can is a big part of their project too so negotiations are never easy with them, summer or winter window. From a negotiating standpoint they went from strength to strength since Laporte has recovered and have an extended contract with higher buyout - meeting the buyout alone does not guarantee sale.
Like I said before though, the way Pep sounded in that pressy - I think they are definitely going to sign someone and either they get a temp solution until a Laporte deal can be closed in summer or they straight away attempt to land Aymeric. Bilbao are doing decent in the Primera and advancing in Europa League so it would appear that the winter move wouldn't necessarily come at a bad time but they are conservative in their business dealings which might mean summer would be preferable. They are a hard club to figure out in all honesty