Event 16 was a bug from previous versions. It's been fixed, but to tick it off you will need to replay the event after you've downloaded a latest version of the game.
event 23 is one of the options you choose from the agent Diaz visit. After completing event 21 you should get a hint from the phone that you will have a visitor on Thursday, and to complete the event you have to pay off Diaz. What happens when you complete event 21 and you click on the hint "???" Is it blank? Does it still say you have to complete 21 first?
For event #16 I did that. I downloaded this new version, saw it wasn't complete so I got her libido to 10 and completed it. Its still not ticked off. Seems minor to me as I still was able to view the content.
For event 23 when I open the phone and look at it, there are red question marks and when I click them it tells me I have to complete event 21 before I can complete event 23. But event 21 is marked as complete - Event 21: Start the photo shoot for HTBYD. Event 22 is complete and says: Finish photo shoot for HTBYD.
I went back thru the gallery (completed event 21 on a prior release) and found the scene available where Diaz shows up and you can pay her $500 or let Lauren pay with favors. So I did that. So perhaps this is just like event 16 and even though I completed it, it just didn't tick off?
Looking at the gallery may reveal some details. For Sydney, despite having seen her in Lauren's bedroom with libido 10 the gallery scene is still locked.
Also for Lauren, despite completing the photo shoot and going thru every single option, only the middle of the 3 gallery options is unlocked (the picture of her in front of the trees with the battle axe and shield in hand).
I have all other content unlocked except for 1 random stand alone gallery scene. There is a gallery page with a lone picture of Syndey and Lauren sleeping side by side in bed (both face down). The next page of the gallery has a single picture but its locked. According to the phone, all content is complete except 16 and 23 and I think I've identified those gallery scenes so I'm not sure what this one is.
I will add one QoL suggestion - give us other skip time options that are easier/more convenient to access. Like in the lounge, let us click t he TV to watch TV for a block of time. In the kitchen let us eat, in the bathroom let us shower etc.
Here's my most up-to-date save (I think):