To your first question: Yes, there will be a Harem a big one or a small one based on how you see it. To your second question: Yes & No, you will understand as the story goes on.

Can't you do something like Stockholm syndrome to make them love him?

You can guess how he will make them love him by his cultivation technique

Is there is any need if they love him or not after all he can do what he want with them as long as he is stronger then girl and her family

Yes, why? 1) seggs is8 better with romance. 2) they won't betray him. 3)always reading/seeing the same thought process of "it feels good but I don't want it" during seggs and other things like a normal conversation feels annoying. 4) why make heroines hate Mc or not love Mc when you can make them love him,support him and be loyal to him without needing to keep on forcing them all the time, just by a little manipulation or Stockholm syndrome?