There's something I don't understand about getting Katarina and Emma to the farm. Can't I take them both at the same time if I take the route of sharing Emma with Mario? Because if I share Emma, Catarina gets angry. So how do I get them both to go to the farm?
Simply seduce Emma but don't share her with Mario and seduce Katarina at the terrace. If you share Emma with Mario but seduce Katarina before that she will still be able to be invited, but Emma needs to NOT be shared with Mario and him getting arrested for her to be able to be invited to the farm and to do her new quest.