We have done baby chicks/ducks several different ways.
I keep them outside since I'm allergic to things and their dust/dander just make me miserable.
A large dog kennel is a great option when put up so you are reaching in to interact or can sit and be at their level. I use sand for chicks. I put cardboard around the edge to keep the sand in (and the dogs out).
I have used a regular light bulb, a heat plate and a broody duck.
I prefer the heat plate. Birds can go in and out as they please when they are chilly. I put press and seal on top of it and replace as needed rather than buying the dome.
The more time they spend around the family and the more time you all interact with them and handle them, the more likely it is you will have friendly birds.
How big of a dog are you thinking of getting - if a large one, get a large kennel. I have a great dane sized kennel (with the great dane and a doberman) and that works great for quite a while for a few birds.
I'd personally keep them somewhere in the house for the first few days and then move them out (they are messy) to an enclosed/protected area outside if you can keep them warm enough or move them to their coop. If you move them to the coop, interact with them a lot.
I don't know of many places, even online, that sex bantams. My understanding is that it is easy, even for well trained people, to injure bantams while sexing them.
I started the last batch in the house in the doberman's baby kennel in my office - on towels. Then moved them to the bigger kennel with sand.
View attachment 2516692
View attachment 2516691
View attachment 2516690