Two things stand out for me:
1. Adam is known to borderline cross the line with others as well
2. Recently, he crossed a line with a mutual friend and he even wanted me to lie about it

'Adam' gets away with it because he thinks he can, and he does. He crosses others' boundaries and they let him get away with it.

No, you are not too oversensitive or overreacting. At the very least, 'Adam' has a blatant disregard for other people's feelings and boundaries. Plus, he is trying to get you to lie for him. I don't want to label or diagnose him but that is scary.

I don't see any redeemable qualities in this guy and I would dump him. That is most certainly not friendship