Shooting children & close up pictures

Its a bit hard to get up close without them knowing you're there...so you must want a zoom lens. If you 'eventually' want a DSLR then you might just want to buy a used DSLR off of Amazon or eBay, and just get into it. I don't know much about entry level Canon DSLRs but The Nikon D3000, D3100, D5000 can be had (with a lens) for under $400 used on Amazon and all three shoot video as well.

DSLR is required a bit or lots of learning, It depends, which level do you want, somewhere between beginner and pro, or pro. DSLR can start up very fast, much faster than digital camera, so you shouldn't miss any important moment with your kids. Nikon is very good at photo quality, but canon is very at video. But I don't think you want to a pro videographer, so a Nikon like d5100, d3100 is a good choice. And about marco photography, I think you should buy a len for that, because marco photography is very special and hard, it's not easy to take a good one.