Hey so I was wondering if it's possible to romance every person or max out the relationship with everyone? I'm playing Jon's route and I think I have the possibility of romancing 4 characters (I don't remember lol); can I romance all four or do I have to choose just one person? 

I don't think you can go for the harem route. It's hard enough to balance all the things you have to do in-game with the limited time. But I might be wrong.

No you cannot, when you oficially date someone others will comment on it. Some, such as Liz will even get mad if you try to romance her when you're already dating someone else