Some questions:
I don't see the harem tag so is it 1 love interests for each play through?
what is the pregnancy content is in this game?
Is it better to start this game first or Summer's Gone?
1 Generally speaking yes though there my be some nuance (The Main character william gets around)
2 If anything like the old build, it will be content probably closer to endgame (I don't remember if you could toggle it off. I think you could.)
3 I'd say play both but start here. They take place in the same world just 22 years or so apart and by starting here you'll appreciate this story as it is and not just constantly treating it as "Summer's Gone's prequel". Also references and details pop up in SG and by starting here you will recognize them and can tell how important they are and will be for future updates of SG.
SG does get more attention however as it is by far the more popular game because of its more marketable premise. So for support SG will get more attention, however the dev has stated he will never drop this as he is attached to it as his first project.