I combined some lists of planned CG scenes, story content, and other changes to have a better overview and visualisation of what should get done in what order.
A higher priority doesn't necessariy mean that something will get done earlier, but it's likely that most things will get done based of this order.
I'll probably add content along the way, but I'll try to focus on the main story and related content, and on finishing existing stories rather than starting new stories all the time.
There are no time frames since it wouldn't work out that way anyway.
Please let me know if you notice that I forgot to add something. Since it's a mix of multiple lists, it's possible that something was lost or forgotten about in the process. Suggestions are also possible, as always.
You can play blind, if you're just playing for fun and for a lot of different stories. The moment you want to finish all quests, dungeons, get all CGs, achievements, and so on, it'll become rather difficult without the included walkthrough or the wiki
The choice for Flaire will just change what events and scenes you'll see with her, not any rewards that have a worth. But you definitely won't get her marriage, once it's added to the game, if you betray her. Just saying.
The choice with the Luminous Order is mostly whether you want to have a story arc or fight a lot. It doesn't have a big impact on anything else.