If we consider STEAM release month; April (as per store description) then we can speculate that v1.8B and v1.9 could be release in shorter time frame or as Hentai Gnome said, they could be bundled together as v1.8B seems more than just hot fixes and patch for v1.8A.
I would hazard a guess the Steam version does not come out in April.
1.9 you are looking at about March/April time. 2.0 June/July. The Steam version then needs an extra character and quest addition, then also needs to go through the approval process so realistically August/September going by previous development cycles. 😭
It is not so much about being locked in, and more keeping in mind this is a side project. Roundscape Eclipse is the main focus, and this will result in further delays to Starmaker. There is still a load of rework to be done, which will hopefully be addressed through 1.8B. Then 1.9/2.0 can be all about building new content to flesh out the gaps and conclude the story.
It is good to be optimistic, but do expect delays. It is better to wait a while for a good game, than a quick buggy uninspired one.