I'm an old dude too, ride burton ions with C60/diode bindings.
I find the stiff boots in the park are a little tricky, but great on the hill.
Your budget is a bit hard to understand, you have a range of bindings but are looking at top dollar boots, so I'm going to assume you're an older dude where budget isn't the main factor given your boot choices.
I'd say get the ions which are cheaper than SLX and the driver X is mega stiff (do you really need that stiff?) then buy genesis or malavita binders for your EVO, this gives you a good match to the board binding combo, and then you have the SL/co2 combo for the hill, I'd put the cartels on the proto or the co2s.
Sell the prophecy and customs, you don't need them.
Consider upgrading co2s to diodes, I love mine, super resposive and super light.
Or come fully over to the dark side, you've got burton boots and bindings already, get an antler for the park, a Sherlock for soft snow, and a custom x for charging.