Glad you liked it! To answer your question, in the 5 chapters released so far, there are some characters who have romance scenes and others who don't yet, even though they will in the coming chapters. There are also some who initially only have romance scenes with one player character but not the other, but that doesn't mean the other player character will never have that option. It's just that each combination of characters is unique, and each connection develops in its own way and at its own pace. Things change as the characters get to know each other, and as different plot points play out.
For Mikael specifically, you can interact with him and change your affection score with him, but his romance scenes are all after Chapter 5. And as Mikael warns you, it's rare for him to feel anything for masculine-leaning people, so the possibility for Althea is easier and sooner than for Farkas. After all, the NPCs vary in terms of how frequently they're interested in different genders.
Also, you won't be locked out of a future romance by an unintentional choice. Instead, either the character won't be open to it yet because you don't have enough affection points, or it will be clear that you're about to lose a character as an ally if you betray them or side with a faction they oppose. These faction choices and betrayal options start to appear later in Season 1.