Offer evaluation for the heating system

Radiator 2 basement and underfloor heating I would avoid.

Radiators in the 2nd basement and underfloor heating I would avoid.

I have mentally crossed out the radiator in the hallway of the 2nd basement for myself as well. Do you still need towel radiators despite underfloor heating? I am unsure about that... In the current bathroom we don't have one and don't miss it either...

That's up to you. If you don't need it, then leave it out.

What do you want it for? Warm towels? Then electric. For additional heating? That doesn't work, better add underfloor heating or wall heating.

What do you want it for? Warm towels? Then electric. For additional heating? That doesn't work, better to add underfloor heating or wall heating.

For me, actually no use case. Underfloor heating and towel rail are completely sufficient. So towel radiator ruled out as well.

Check if the heat pump is modulating. If not, I would have an alternative offered that can do that. The drilling should be designed for a 9 KW heat pump. What kind of house are you building? 9 KW seems high to me.