1. I agree with the boiler guys. If I ever get the chance to build again, it will be a boiler again but with a good layout of zones.
2. I have to try and change your mind about the A/C though. My wife demanded central air conditioning to be installed in our house while it was being built in 2004-2005. Summer of 2005 we hit a hot dry spell...that A/C was seriously used during those days and every summer since. We live in a neighborhood out in the country. Yes it is breezy and it is not hot all summer long but when that breeze stops, windows close and...thank God for A/C. The neighbors laughed at us because we moved up from Virginia, told us we don't need A/C in PA. Since then the "laughers" have installed window units in 3 of their rooms. It is now winter time and those window units are removed and stored somewhere....garage? basement? attic? closet? My central a/c is just turned off.
Have it installed and added to your mortgage. If you don't have the whole job done at least have all the duct work done while the house is being built. If you go with the coal hot air furnace make considerations for central a/c also.
One more thing. Not to knock coal or anything but if you are building a home around coal as you only heat source...God forbid...what happens if you are injured or disabled to some extent that you cannot handle the chores of coal heat?
I grew up in a home where my father suffered from heart disease. I was the youngest and last to move out (1984). It wasn't long after I left that they had to switch from coal boiler to natural gas boiler because those coal chores were just too much for Dad. Dad passed in 92, Mom is still in the same house with the same natural gas boiler that uses the majority of the same plumbing the coal boiler used. Conversion didn't kill them because not much plumbing work had to be done. (gas prices now are hurting her though
Suggestions: get the A/C and consider all opinions for heat sources. Southern facing wall with windows means you likely will have a southern facing roof for Solar panels. Example: Check out http://www.radiantsolar.com
"Solar Options" "Solar Option II". (It's an idea). Don't want to do Solar but maybe in the future....have the plumbing run while the house is being built. Solar power for the future? Have the wiring run while the house is being built.
Just some ideas. Hope it helps. If you want to know the mistakes I made while this house was being built, let me know.