Everything including the kitchen sink

Hi all, hope your New Years all went to covid restricted plan, we were in bed by 11am, and on top of pen y fan by 9am the next morning. 
anyway, I’m sure these questions have been asked a million times but can someone point me in the right direction to get the answers 

1) I’d like advice on the build up of the floors, I want to install UFH throughout and want  to get the depth I need to excavate, and the size of the insulation etc bang on

2) cavity insulation type, size recommendations etc, when I built my current extension I used 50mm kautex in the cavity and find it extremely cold, I would like to install something better in the new place 

3) smart things camera control- I’d like to integrate HIK vision IP cameras with smart things control, so that I can programme it to trigger a light if someone comes on to my property, has anyone done anything similar?

4) best smart heating control for all round control. What are you guys using, currently use nest thermostat 

understand these questions are vague but appreciate any help at all