I'm not sure if I am right here or not but something in the way you compose your posts herein tells me that you, Newfie_1986, are not really into getting much in the way of advice and, honestly, drawing an analogy between a trigger job on a Rem 700 footprint and installing a back-up camera system on a new pickup is, to be most charitable, a gross exaggeration of what is required.
Anyway, if custom is an idea that you are toying with, then I am going to recommend that YOU learn a lot about what YOU want before starting out as many of the questions a reputable builder will ask will require that you have a decent amount of knowledge so that you can make intelligent decisions and work collaboratively with the builder of choice. As far as a builder is concerned there are many excellent choices in Canada: Insite has already been mentioned, you mentioned ATRS, Casey at Tac Ord comes to mind and, of course, the very excellent Chou Bros to name just a few.
Incidentally, Ross at PGW is truly first-class to deal with and will likely be able to guide and advise about trigger options. Finally, I don't believe that the PGW chassis systems are made by Cadex but, on this point, I may be mistaken.
Whatever way you go I am sure you will get a good rifle as there are no bad choices listed so far.