harem in the meaning of dating several girls, yes. Harem ending, not planned, but probably possible in some way. Pregnancy, can't say for sure. Probably at the very end on some paths.
Viewing post in How to Fix the Future | Chapter 2, Part Three comments
To be honest, I really want to persuade you that in the case of a drastic reduction in population during an apocalypse, having a harem ending is quite normal. In such apocalyptic situations, maintaining the population is the least humans can do. At the very least, the future girls should be able to accept a harem; I can understand that Chloe cannot accept it because she comes from the past. I hope the author can reconsider. I really love this game.