Hot side aeration (HSA) is very different from post fermentation aeration (PFA). HSA is a problem for long term stability and shelf life of beer. This is much more a problem if the beer does not have any strong flavors (eg American Lager or Helles) to cover the defects. Also the darker kilned grains, like your choclate and black malt, should help with shelf life issues. It sounnds like your beers are bottle conditioned, this will help the your beer last as well.
As for the PFA this is what give the instant wet cardboard flavor. If you are indeed bottle conditioning, you must have aerated the living crap out of those bottles. Reasonably small amounts of O2 in the bottle will be scavenged by the yteast durring refermentation. With a massive amount of O2 in there I would expect a yeasty cardboardy flavor, becoming oily and fetid. Give them a few month and you will have wonderful presents for people you dislike.