OK,
So for the Aeroplan Card it depends how quickly you want the points. Remember it is always best to around 3 months between each new application. Without knowing when you applied for all of these cards it is difficult to say if you should apply for another. Again I think others here will have different opinions. I would just ensure not to apply for anymore than 2 or so every 3 months. However in the worst case you will just be denied however I have found Amex to not be as strict as some other companies at accepting apps. I.e. Capital One are horrible and you should only apply with them if you 100% have to..
With the AMEX Gold you will be able to transfer to Hilton and SPG. I would not transfer to Hilton based on the devaluation earlier this year and SPG you will loose a lot in transfer. However I do transfer AMEX MR points from time to time to top up my SPG account. The best transfer partners would be Aeroplan / BA Avios ( for short-haul)
For the AMEX Plat see this thread
http://www.flyertalk.com/forum/ameri...x-plat-22.html Yes the other passes you can just give to friends. I do not find the Priority Pass very useful and remember you have access to all MLL passes with your plat aeroplan card. There are certain AMEX Platinum lounges doted around however they are on the same level as the MLL.
For the fast track with Fairmont you will need to pay with your AMEX card. If you can see yourself staying 4 nights then for sure it is worth it. Remember you can always book through Aeroplan.com to be able to get breakfast,upgrades etc. or book through a Virtuoso agent or AMEX FHR. Correct no stays will count.
Hope that helps, others will chip in if I have missed anything..still early on the east coast
Alex