It looks like you're making good choices here - the MEC tent seems like a good 3 season tent. I own a similar REI Half Dome, an REI QuarterDome, and a TarpTent Double Rainbow, they're all good 3 season tents. The extensive bug screening overhead on the REI models is not really an issue, you put the rainfly on, they're water tight. The Half Dome has the best space for 2 sleepers, the Quarter Dome is lighter but too small for two adults (okay for 1 adult and 1 kid though, if you don't mind squeezing in). I've also slept in the MSR Hubba Hubba on Scout camp outs and its a good tent too, ours was a 3 person model and it is very large. A bit heavier and bulkier than the REI Half Dome. I like the simplicity of the Tarptents most, they're lightweight and plenty water tight. I use my Double Rainbow as my solo tent, but I could fit a couple sleepers in easily enough.

A word of caution on extending the tarptent or any 3 season tent into shoulder winter seasons, you can get snow infiltration in a tarptent along the bottom, because there is bug screening where on other tents there might be a solid nylon panel, I've been out in October-November and snowed on and you do get some snow in your tent that way. They're not really designed for winter conditions, and though they'll work in a pinch, you shouldn't trust them to perform for you in snow situations. But I've been warm and dry in all of these tents you and other posters have mentioned.

If I had to choose a tent to be marooned in for a couple days of absolute downpouring rain - probably go for the Double Rainbow camping solo, or the Half Dome if camping with a friend. There'd be room for both of you and a deck of cards anyway.