Who is owner?

If land is purchased using HUF funds, then HUF is the owner. There is no legal bar in Karta constructing building in the land with his own funds if the members of the HUF are also agreeable to the idea. In which case, the land will be hUF property and building will be Karta's personal property.

There is no natural right for the Karta to construct the property with his own funds.

if building constructed using karta individual  funds on huf land, then where to claim income from house property

to claim income from house property, is it necessary land and building are owned by same person.?