Can I MQ to myself?
 

Can I hand in half, camp out, log in alt and hand in the rest?

I've done this

I did this for HS key

If your quick enough and no one is around to screw up your MQ sure. As stated i've done this for a few HS keys.

I've always wondered, do MQs have a hand-in timer?

I know that Sakuragi was doing a MQ for monk epic and handed in the first part, and he received the monk epic. Oops.

I am uncertain if they have a timer. I vaguely remember it was old practice that before any turn in, you'd hand in 4 Water Flasks to "clear" the mob's inventory list before doing any major turn in of your own.

I've done this for myself for jboots, hs key and seb key.

I did this for Rogue Epic . . . that's how ballsy I am

This.

How is this ballsy? That's like saying you are ballsy ordering something from amazon.com. It's not ballsy when you know for damn near certain it will work.