PSU, Fans, and mobo connection question

Hello all, put together my first build recently and had run into an issue where I shorted my chassis fans out accidentally. I did a few searches online on fan connections and didn't find much unfortunately, so I figured I'd pose my questions here to see if maybe someone could enlighten me a bit.

First a little background, I have a Lian Li K62 case. It has 4 fans (one front, one back, and 2 top) that are all 12 volt. I hooked them up in series on one cable coming from my Corsair 650 watt psu, and connected the end (a 4 pin adapter) to my mobo at another 4 pin adapter.

My mistake was obviously not checking the voltages. The 4 pin adapter was 5 volt and one of the pins wasn't necessary for my need, thus shorting it out.

Anyway, my questions (if anyone can provide help) are as follows:
Is there any issue having all 4 of these fans on one line from the PSU?

I shorted out the end of the line and it smoked up a bit melting that wire. I can disconnect that portion and run the fans without being connected to the mobo. Is this an okay set-up for now (being my first set-up, I will fix this as I want to do it right, but in the meantime I want to know if it's dangerous or not)?

I believe the proper fix to this was to connect my fans to the 3 pin 12 volt Chassis fan connector on the mobo (once I get the wire fixed), is that correct?

Thanks for any info you might be able to provide.