Originally Posted by b_magee

Thoughts on some of your questions:

A) I'm partial to row 4 D/G (middle pair) on the A359... that way each gets an aisle. But I believe the odds of getting the 1-2-1 config are pretty low... so you could take A/C (window/aisle) and be fine. They usually load the actual operating aircraft seatmap about 48 hours ahead of time. Either way, you can check the evening before your flight what aircraft will actually be operating (since it travels to YYZ the night before). They've also been swapping for 788/789 recently too according to FlightRadar.
B) Similar to above... note they also frequently put a 777 on this route (2-3-2)... so best to go for a window/aisle if travelling in a pair...
ET swaps aircraft around fairly freely (sometimes even day of), so until you see what's coming to you, you can't always be sure.
C) Maple Leaf lounge (Air Canada)
D) Drawing a blank - but I think its either the Lufthansa or Turkish lounge.
E) Probably not since you will be in Economy via ADD**** (sorry, misread this) and they will look at your onward ticket - Unless you have *G status then yes, you should be able to access the lounge. I haven't been through recently, but I know it was mentioned about restrictions for guests coming into lounges (due to CoVID/capacity/etc). ***So I think one of the adults would need *G to consider it. Under normal circumstances, 90 Minutes normally would make for plenty of time for a lounge visit in ADD.