I'm a firm believer in "locked/hidden" content. By that I mean: you get locked out of certain scenes, dependent on the choices you make. This project was never about seeing everything in one go, but rather following your choices in a "meaningful" way to you (the player).
Every choice you make matters, but not all of them are as impactful as others just yet. The result of some of the choices don't show themselves immediately but that is the problem with incremental development in a project such as this.
An example: In 0.4 you could chose to take advantage of Jo in her state of inebriation, but that choice first showed it's effect in 0.6. A lot of the choices are that way - they take time to come to fruition.
We did indeed start out with needing to go down a road with either: Jo, Nat or Mary. But as time is passing that choice is slowly losing its meaning and the "stats" are becoming more and more important in the future. Especially since he will be able to make use of his energy more frequently. He is still learning and is still only dabbling, but eventually his Focus will increase and thus he will find the energies increasingly easier to manipulate.
Okay, this became some kind of rant and I don't even think I answered your question in that, but I'll leave there anyways
You will be able to "pursue" a relationship with every character that has visible stats. It all depends on how and when this relationship becomes available. Again your choice matter in that respect.
Hope this answers your question.
Anyways ... you all stay cool and have a good one.
Cheers - Kaffekop