for the first 3 questions:
1-you have to be a little bit reluctant to set her free, so she offers you stuff in exchange of setting her free. as i remember you only have two options (scenes) with her, and yes since you basically fuck up by setting her freethe master leaves you, by doing so you lose:
-the chinese dress
-in case you were doing the slut route of anna a threesome scene with him
2-this part is more of a caution for you, if you cooperate with her you have to be carefull with emma (the daughter) and katharina (the wife) progress them first, the wife is easy, but with emma you can fuck up easily. progress marios route until he ask you to corrupt her, choose the lie option and keep visiting emma in the sauna, when you reach the option to tell her that mario wants to have sex with her, dont tell her and pick the other option so you are able to keep having sex with her. because if you let mario fuck her and then betray him she will be angry with you and will lose content with her, and as of right now there is no way to fix your relationship with her.
now the diferences between the options:
2.1-if you cooperate with her they arrest mario and you unclok her house to visit her, go there like 3 times and you will see a note, saying that mario captured her and that you have to go to the forest. you will need the athletic perk (and if you want the living weapon one), because when you get there you will find two guys want to fight/kill you, they are marios goons, for them you need the atlethic perk.after that you get to mario threatening to kill sofia, you can knock him up or kill him (the living weapon perk). and to finally finish xd after you rescue her you can visit her at her home and have a sex scene
2.2- now, if you betray sofia you can corrupt emma with no issue, what happens is that basically marios goons take her and make her your sex slave, this way you unlock the guest room in his mansion.
3-depends on you, if you took the slut route for anna make him stay and share her with him, you get quite a good amounts of scenes, if you made the pure route there is no much reason to make him stay, you will lose scenes but will get different ending options. now, i dont know if this was intentional or not, but by accident i was able to share anna even when i did the pure route, wich didnt make much sense (for me at least) but whatever xd, i was able to get the sharing scenes even though i was in the pure route, ah but you wont get the slut route exclusive scenes, like the gangbang on starcon
now the general questions:
1- honestly i really dont know
2- at least for now thats it, unless im missing some stuff to xd, but as far as i know thats all there is for now
3-for as long as i played this game (since 1.2B, yeah im basically new here) it was basically luck for me, i guess you need to have certain progress with anna and keep visiting the bar until she appears
sorry for making it long and my english, i hope i made it clear since i still need to keep working on it xd