I don't recall where it was explicitly discussed, but aren't Skywalkers priced as Chunin-grade seals +50%? They're based off Air Domes which are only Chunin-grade in difficultly, I believe.
Since there are only 3-4 jounin Sealmasters in total, raising them to Jounin price would increase cost by 300% while only increasing output by 30% (less if Hazou/Kagome constitute the majority of Skywalker output already). Leaf could do it if they were truly desperate for the production, but that state of affairs wouldn't last longer than a few months.
I think when we modeled it, given the demands Hazou has on his spare time, seal income has the potential to make you quite wealthy, certainly enough to deal with the mortgage and enjoy an opulent lifestyle on top of that, but it would not be enough by itself to deal with your political issues. If you ramp up seal output to its sustainable limits (assuming the focus inherent to scribing blanks + infusing limits productive labor to 8-10 hours a day) you could afford to buy out the Hagoromo with money to spare*, but pre-committing that much time would cripple your other plans.
Hazou is your only output vector into the world, if he spends all his time making seals then he won't have time to actually carry out your objectives. Similarly, Kagome is your primary source of advanced sealing research, if he spends all his time on production of seals to sell (assuming you could even convince him to do so, given his paranoia) then you are basically trading your seal researcher for mere money.
If you adopt a sealmaster you could mitigate this, but (precisely because sealing is so lucrative) they are already among the most well-compensated professionals in Leaf, vastly more so than field ninja, so are the least needful of clan backing. Thus it is in your interests to find some means of generating massive wealth that is either even more lucrative than sealing or that does not rely on your continuous personal contribution to maintain.
*As in, your monthly income would be enough to absorb their debt with a significant amount left over, not that you would make enough in a couple months to buy out their principal.