Out of curiosity, are the side quests linked to the main quest in any way? meaning do you have to progress a certain distance in the mains before you can progress further in the sides? Also, I seem to be stuck on Catherine. It only has the one scene and I cant seem to figure out how to unlock to continue. I've seen image posts so i know they exist, just can't seem to figure out how to proceed. Thanks in advance!
Even though there are Main Quests, Side Quests, Case Files etc. they are all basically just quests. They story is basically linear, there is no branching, only scenes (and dialogues) variations depending on player chioce. The quests (unfortunatel) allow players to access some contents not in the right sequence, so you might notice some dialogue inconsistencies.
In short, you basically have to do all the quests to progress the game/story but I don't know the right sequence either. Some quests are properly locked behind another quests while some other quests can be started immediately but you cannot pprogress it until you have completed or reached a certain point in other quest. Example for that is
Sage quest (you can find her in the SteamyBeans Cafe
Mia works at) where she asked you to investigate her boyfriend (SteamyBeans Cafe owner). You can activate it very early but you have to progress significantly the bar quests before it will continue.
As for the Catherine scene, not sure what or which one you are referring to. Just do a catherine search on this forum and you will find a lot of 'guides' for various scenarios. If you don't understand something then you can reply or ask the poster for more information.
Hope that helps. Cheers.