"Would you do electric or hydronic? " As a guess, your baseboards are probably being sent water from the boiler that's in the vicinity of 160-180 degrees. That's too warm to circulate in a floor. It would make sense to put the RFH loop on it's own isolated system. You'd probably want a mixing valve to drop the temp from the 170-ish boiler temp to 120 degree water which is more suitable for a RFH loop. You'd probably want a circulating pump to move the water through the loop. To make it all happen you'd need a few valves, t-stat, relays, etc, etc. Or you could buy a small water heater, set it at 120 degrees, and use that to heat the loop with a t-stat to kick it off and a circulating pump to move the water. As well as a few more obligatory bits and pieces. That secondary system would be completely independent of your boiler and whole-house baseboard system. To warm the tile floor, you need a RFH mat wired on its own circuit. A t-stat. Which is easier? Which is less expensive? When you wrote this: "We are still keeping a heating element in the room so we aren't looking for it to warm the room." I'd recommend electric radiant; mat or cable style. It's easier to type and easier to install.

Just a suggestion for re-arranging so you have a full wall in the dining that is not broken up by the entry into a bedroom. You can have the entry from the mudroom or from across the peninsula. I'd also consider moving the door for the master down more towards the corner for more privacy from the living room. The other thing I would consider for your kitchen is an island to create a walkway from the mudroom into the house so people doesn't spread into the kitchen and then remove the peninsula part. You'll get more use out of your cabinets this way too and it will feel less tight against the dining room.

need phone call

It takes mine 20 minutes to fill all the way - thus I don’t always do that!! I’m thinking it may be because it and all the faucet stuff replaced 50 year old stuff. At least that’s what I understand from the plumbers!