Best way to store beer is probably a well sanitized keg at fridge temps. If you're looking to age beer, then I would go with a well sanitized bottle at 55f or so.
When you're looking to go long term sanitization is very very important. Sour flavors would indicate infection. Also you want very little oxygen. Either bottle condition or counter pressure fill from a keg.
As for your beer, I would crack another maybe it was just one that evaded the PBW and star san. If you don't need the bottles you can let it sit longer and keep your fingers crossed. But I would go a bit colder for sure.
Scottish 60 Schilling
Easy Jack ISA clone
In the Carboy: