Nurse Nina
To get the scenes from the Nurse, you have to get defeated in battle (Fighting spirits / Mario's goons) and got sent to the hospital 3 times (it won't work just by visiting the hospital normally). 1st : Chatting ; 2nd encounter: Handjob ; 3rd encounter: Choose the dialogue carefully and you'll get to have sex with her
Josef, Anna & Adrian
After you decided to be in an open relationship with Josef, Anna & Adrian, the scenes afterwards are spontaneous around the house and doesn't have any specific day to trigger (Except Camping on Wednesday, Pool on Monday, Gaming & Beach on Tuesday). You can find these scenes around the house (Including Wardrobe) and the update gives you 1 new scene and 1 repeatable scene which are located in Master Bedroom.
Sofia
After Mario got arrested and you have found a memo in Sofia's House, make sure to get the Athlete Trait activated first before going to the "Shack". With it you should be able to defeat Mario's goons and you find that Mario is holding Sofia hostage. You can choose to knock Mario down or kill him (I chose to knock him down) and rescue Sofia. Go to her house and she'll open up with you can be intimate with her (I think this is as far as you can go with Sofia for now)