Q:
Heirlooms?
Nobody knows for sure except devs and those on an NDA neither of which are able to talk. Personally I doubt there will be, it hasn’t been Anet’s style to re-purpose special currencies.
It’s better to keep your mouth shut and appear stupid than to open it and remove all doubt.
It is reasonable to expect there will not be new uses.
Considering the teasers we have for Lion’s Arch invasion, and the non-english sites confirming (directly/indirectly) that March 4 would be the last for the rescue portion, we would be getting new content within Lion’s Arch (and the drill).
Of course, however, it could happen that Heirlooms will be acquired in a new way for the invasion portion, which could introduce new items to be purchased.