First off, Goose do we know each other? If you're interested in more details about the clubs/personalities, feel free to email me (joeolson2009 gmail)
A lot of this is based on both the club and her experience, but I'll do my best to give you some estimates.
1. Local team head coach [Local team are pretty much an after-thought. It's likely going to be 250-300 dollars a month w/ 1 practice a week if it's a younger group and maybe 300-450 if it's an older group that practices 2x a week. I would generally recommend to stay away from this if your wife enjoys coaching vs. being a cheerleader. Most of the girls that are playing local have no real chance of playing in college, but that doesn't mean that the parents necessarily agree.]
2. Regional team head coach [Not a huge difference between Local and Regional, but I'd guess Regional might just travel for 1-2 out of state tournaments. So consider this more of a 2nd, 3rd, etc team ... As always depending on the club, but you should be making 600+ at least]
3. National team assistant coach
4. National team head coach
For 3 and 4, it's really difficult to guess. For some clubs, it might be 650-800 for an Assistant job while it could be 500 at another club. For Head Coaches, things are all over the place based on experience. I don't know what the Head Coaches at TAV/Skyline are making, but I can imagine that LJ, Ping, Landon, etc are doing pretty well. (Maybe 1300+?) but they are the exception. It should be safe to estimate north of 750 for most clubs, definitely for a top 10 team.
Make sure you address per diem, travel expenses, clinic expectations, etc. Some clubs have 2 practices a week and then a mandatory positional for each coach. That might be tough for your wife with a new child. Look into private lessons at the club - how much does it cost for court time? How often do people normally do this? Does your wife have a specialty - ie could she run a setting clinic? That's where you can really start to make some money over the summer. $20/kid for 2 hours with 3-4 coaches can be pretty lucrative if you build enough interest and provide consistent value.
Hope this helps.