Yes actually. You can unlock explicit content and romance routes with almost everyone on a single playthrough. But it’s a harem for story/scenes only. You are still restricted by companion capacity mechanical limits, so you can't have them all follow you around or fight together at once.
Yes! But for Robin tho ⚠️SPOILER ALERT⚠️ in order to progress the intimacy with him, you gotta enhance the pill the moment you first see and take him. If you just paid for the treatment and didn't talk abt "enhancing the pill" then he would be a man and you can no longer progress the intimacy with him. (No sexual intercourse. Well this is just as far as I've known cuz I've played every choices and checked every outcome 😭)