How to tell a guy is genuinely into me, or just being friendly or can be deemed as a bit weird?

Concerned that he holds eye contact while talking? No I don't think that is a real concern, people are different, some have more eye contact some less. It might also be his way of reading you?
On the name part I can only speak from experience; I absolutely suck at remembering names! I have a pretty good memory otherwise but names are embarrassingly hard to remember... So that might just be it.
Opinion
2Opinion
He will express more than a casual interests.
If he acts like a weirdo you can tell
Superb Opinion