we have been using the Andor Zyla sCMOS camera for about 3 years now and are quite happy with it. It comes as camera link or USB3 version, of which the latter was much more practical to use (we have 3 of these now, 2 USB and one older CL). To your questions:
1) Programming API is pretty good in my opinion, it's a C library that also exists in a precompiled form. I imported the DLL to python and went on from there.
2) There are a number of trigger options, which should enable you to do what you want. E.g. you can trigger via TTL input. The shutter is fully electronical, global or rolling. The camera is also pretty fast, up to some 50 Hz or so if you really push it hard.
3) Pixel size is 5,5 um, the sensor is 2560 x 2160 pixels, which gives us (at 3m focal length) a FoV of 0.3 deg and a scale of 0.5 arcsec per pixel. Pretty useful. And it's cmount.
4) No problems whatsoever so far in rather harsh outdoor conditions. The camera is also rather small and lightweight, which is also nice.
I can also mention that we tested two other cameras that were less useful in this context: First a FLI astro-CCD that had a gigantic chip and thus FoV, but a slow shutter and readout, so you could only take one picture every five seconds or so, and the timing was not accurate either (otherwise very good camera). And an Andor iXon emCCD which is very sensitive, but the camera is somewhat bulky and heavy and the chip is rather small. Unless you expect very low light levels I do not see much point in using any emCCD at the moment.
Ah, and maybe good to know: You'd pay something like eight to ten thousand Euro for it. Maybe a bit expensive for your needs, don't know.
If you need a rather cheap, reliable camera, I can recommend pretty much everything from PointGrey. Sturdy industrial cameras with a good interface, high frame rates, small size, cmount, ethernet or USB connection. Not very sensitive and not very large chip though. We use them for beam monitoring and occasionally on our transmitter telescope.
Hope that helps somewhat...