Well, having your child photographed by pro does not come cheap so instead of doing that, I'm going to purchase my very first DLSR camera, debating on Canon 60D or T4i...
That was actually one of the reasons I bought a T1i, several years ago. (But, photography was a big hobby for me many years ago, in the pre autofocus SLR days, so the T1i was also a trial to see if I wanted to pursue photograhy as a hobby, beyond family pics...and the answer there was yes, which explains my current gear list.)
If you get the T4i, the 18-55mm kit lens is a good idea - adds relatively little to the cost. The 18-135mm lenses offer similar IQ (i.e. decent, not great) over a broader zoom range. While the cost differential between the T4i and 60D is not huge (when considering something like the 6D, anyway), it would help to know what you have in mind for a total budget.
The 85mm f/1.8 is a great lens for tight portraits on an APS-C camera. In general, you have the right idea about spending more on a lens.
The other thing to consider is lighting - you mention portraits, and while a fast prime is great for candid and outdoor portraits, have you gone to a 'chain' photo studio (Portrait Simple, etc.), and checked out what they use? Usually an APS-C body with a kit lens like the 18-135mm - and that works well. Why? Because with control over lighting and the background, you can shoot at the sweet spot for those lenses on APS-C (f/6.3-f/8) where they are optically quite good. When you buy an expensive prime lens (L-series, but the 85/1.8 is close) you're paying for the ability to shoot wide open and get sharp images.
At a minimum, I'd recommend a 430EX II flash so you can bounce the light off the ceiling indoors. You could consider a portable backdrop setup for your house, more lights, and some softboxes.
My point is that there are many options, depending on what kind of images you want. But usually, lenses (especially for outdoor portraits) and lighting (especially for indoor portraits) will mean more for your final images than the camera body you choose.
Personally, I started with a T1i, EF-S 17-55mm f/2.8 IS, 85mm f/1.8, and a 430EX II.
Shots like the ones below were taken on a FF camera with an L-series lens, but you would not be able to tell if they were taken with a Rebel and 18-135mm - they were taken with a zoom lens set to f/9 or f/10 (the 'sweet spot' is a bit narrower on FF vs. APS-C), with three lights in softboxes (one monolight and two Speedlites) and muslin backdrops on a portable stand.
These two were outdoors with an 85mm prime on APS-C (T1i+85/1.8 on the left, 7D+85/1.2L II on the right). The wide aperture helps to isolate the subject from the background. You can't tell that the background on the left image is a dirt path - that's why subject isolation is a good thing!
You also mention low-light landscape and cityscapes - for that, you're going to want a good tripod and ballhead. Get a cheap one, it won't work well, and you won't use it. I'd consider Manfrotto as a good compromise between quality and value, carbon fiber if you plan to carry the legs any significant distance.
Also, take a class on learning to use your dSLR - get it out of green square (full auto) mode. Check community colleges, also where I am the local Audubon society offers frequent dSLR intro classes.
Hope that helps...