Hurry up and do it while you can! I thought the bouncy seat worked pretty well around that age. I would set him up in it and orient him in an attractive way toward the window to avoid using strobes.
This was with the 8x10" Sinar P, 4x5" sliding back, and a 6x7cm rollfilm back (sounds like overkill, but it was set up on a studio stand, so it was the handiest camera I had at the moment) at 15 days old--
8x10" Sinar P and 4x5" sliding back again, this time with a Polaroid holder and Type 55, and a modified Busch Vademecum lens in shutter so it has a larger maximum aperture than the barrel, producing that diffuse focus effect. In the bouncer again at about six weeks--
The sliding back is a big help with this.
Here's one in the stroller with the 4x5" Tech V, DaYi 6x17 back, 150/4.5 Xenar, handheld using rangefinder focus. Close focus produced a little vignetting with this back, so it's more like 6x15.5 cm than 6x17--
Once the baby can move around, I recommend an SLR with rack-and-pinion focusing (Graflex, RB67, Rollei SL66, etc.). I was using my Bronica S2a for a while, thinking it would be easier than LF, and then realized that the bellows was easier to focus than the helical (these are interchangeable on an S2a), and the chimney finder was brighter and quicker to use than a prism or waist level finder. In other words, I turned it into a medium format Graflex, so I switched to the 5x7" Press Graflex, which I now think is the ideal camera for toddlers. Here's one at about 14.5 months. The lens is the 210/3.5 Xenar, probably wide open or close to it--