Quick question, does the damage your Familiar inflicts effect your experience gained? Like, do you gain Constitution or any other form of combat-based experience from THEIR attacks?

Yes. The different familiars give different types of XP. Here are a few examples:

 

Steel Titan: Ranged

Wolpertinger: Magic

Swamp Titan: Attack

Lava Titan: Strength

Iron Titan: Defence

So it's based off of the familiar's attack. So Magic Attack Familiar gives Magic experience. Gotcha.

 

How about Constitution, how does that work for familiars?

Simply put, it does not work with familiars.

I just want to make sure Constitution isn't gained. I'm considering doing this on my mage pure, for different reasons and if I decide to do any battles, I don't want to gain Constitution levels because of it.

Combat familiars give no constitution xp, sorry if I was unclear.

Not at all, I just needed confirmation a second time, since I don't want to risk my current level :-) Thanks!

Just so you (and anyone else curious) are aware, you were wrong. Familiars do contribute to Constitution. Tried it out just to see and I gained a couple of xp points during an attack I sent it on.

Familiars give the normal xp, so also constitution xp.