Return to Murder House

Was rewatching that episode last night and a couple issues occurred to me.

Why did Constance just block Moira from interacting with her? Like Violet did to Tate, and Vivien to Ben?

And why did they hop through the hoops of the realtor? Couldn't they just magic their way into the place without anyone knowing? And therefore not have to buy a whole house for just a day or two? Because the info the realtor gave wasn't worth that much