Separate heat and hot water systems for two apartments

we are in the early stages of renovating the ground floor of our duplex after devastating water damage when we moved in last year. if we decide to redo the slab, we will embed pex for radiant for that level, and plan to staple-up between the joists to heat the upper level of the duplex. i am on the hunt for reliable and knowledgeable heating contractors, who don’t mind teaching me as we go, to guide me through it. if you have any tips or recs, they are much appreciated. i’ve been scouring the web and getting quite an education on radiant heating.