Phones are useless for anything night aside from maybe some video options, like time lapse or slo-mo. DSLR's shine at night because of the ability to open up that shutter for extended periods of time. One thing you should invest in, should you be after lightning/night time structure, ifs a wireless remote. That can be had for super cheap on amazon and are a great tool to keep on hand.
And like you said, if you already know Canon, stick with it. Canon is great. Nikon is as well. Just depends on where you started. Canon vs Nikon is not nearly as divisive as the PC vs Mac or iPhone vs Android communities. Camera people just like cameras and nobody (with any sense of decency) will give you shit for which brand you like.
Go surf craigslist or local pawn shops if you're just getting started and want to try out a few different camera bodies or lenses. You'll find that most people here have a kit lens, a telephoto zoom (usually in the 50-200mm range), a wide (say 14-20mm) and a prime fixed, like a 35 or 50mm. Personally, I run a 18-55 kit (rarely use it though), a 14mm ultra wide and a 70-300 tele-zoom. All cheap glass. Nikon branded lenses are expensive compared to brands like Sigma and Rokinon, who make great lenses for a fraction of the branded lenses.
bhphoto.com is a useful resourse, not just to buy, but for reasonable and informative reviews of products. Worth taking a peek over there as well.