For irrigation only use an irrigation pump, eliminate any pressure tanks and pressure switches. You have something similar to an above ground pool with the pump sitting on the ground. Irrigation pumps are generally 1-hp, 1.5-hp and 2-hp for residential use. Another is your power, 120v or 240 volt. 1-HP is 120v, 1.5hp can be strapped for 120 or 240, 2HP is always 240v. For intake you want a 2" pipe, outlet is 1.5" or 2". 1.5hp and 2hp it will be 2". 1.5HP is usually the best all around size but it depends on lot size and the number of sprinklers, type of sprinkler and the number of zones. For ease of use and reliability, Rainbird controllers work best for residential use. I've had Hunter and Orbit controllers and I find that Rainbird are very good for the money. I have a Wifi Rainbird and I love the fact that I can irrigate on demand at any time and from anywhere. Zone valves and pump start relays of any brand are the same.
Brand pumps, just keep away from China made stuff and Harbor Freight pumps. Seals and parts would be almost impossible to find. You'll find most are now made in Mexico including the motors. Hydro glass or cast iron pumps are about equal in performance and reliability. Either one will work just find. Even with cast iron housing, the impeller and seals are the same as a hydroglass unit.
I've never had a pump below the water level and I'm not sure if siphoning will occur when the pump is shut off and the zone valves are closed. I think it will be OK . For winterizing you'll want at least two spigots, one to drain the feed pipe. It would have to be above the lake level to allow air to enter and break any siphon. Another lower to drain water to the pump to keep from freezing.
