is it possible to trade in the digital version of Pokemon Gold?

Solution 1:

Yes, From the press release it says you can use the wireless features just as was done in Red/Blue/Yellow with Gold and Silver.

As with the Virtual Console versions of Pokemon Red and Blue, and Pokemon Yellow: Special Pikachu Edition, Gold and Silver will be compatible with the 3DS wireless communication feature, which means Link Trades and Link Battles between the Virtual Console versions.

[Source]