Good question.
This woman discusses her work in the astral plane, and a variety of beings she encountered, including ET's .... the point being, some are indigenous to earth , and some are not.
She mostly talks about military remote viewing but mentions this towards the end.
http://www.youtube.com/watch?v=TYO-iABnQd4

Interdimensional typically refers to anyone, any entity, angel, spirit, ghost, ET, not normally visible in our physical dimension.
Some are able to manifest-transition into our visual reality, and there are those who reside in astral realms (and this is likely what some regard as inter-dimensional.

Searching this terms definition... provided no clear demarcation between those who reside in other dimensions, and those who transition between dimensions.


The 2012 topic has filled several books.... and more info is yet to be revealed.


Well as far as disclosure, it's inevitable, in some form.
(disclosure generally refers to the govt's sharing their secret UFO documents)
Frankly the lies go so deep, I find it difficult to imagine our govt coming clean about what they know.
But many suggest they're deliberately leaking information, to gradually do this.

As far as contact.. it's ongoing... and the sightings are massive... if one cares to look beyond Fox-CNN news.

THIS aspect of disclosure is the one that I'm familiar with...... http://www.disclosureproject.org/