Without me having to do all the math. What is the highest distance from the top of water in the well to the highest place you will need water and at what max pressure. Like maybe 40 psi for sprinklers or maybe a shower if it's higher. What is the max flow needed for the fire sprinklers? What is the max flow needed for your irrigation and house needs.
You may be ahead of the game to put in two pumps. One for the home, the other for the sprinklers and irrigation. That would keep the fire sprinkler pump exercised and you could put in an irrigation system that could make full use of the fire pumps capability.
I am not a fan of VFD's and do like CSV's. I would recommend one for each pump and bladder tanks to go with them. Get me the specs above and I'll size a couple of pumps.
By the way, do you have the level in the well that the pump broke vacuum at? Is that maybe the pumping level or how did they arrive at this figure?