I'm hoping somebody can identify a couple components on this motherboard, so I can replace them and hopefully get it running.
The board is an Intel "Performance/AU" or "Aurora" 450KX for Pentium Pro. This board is also in branded systems - this particular one is from a 1996 Gateway.
[the short version]
The parts I'm trying to identify are:
(mosfet?) at Q1J1 - it has a clip-on heatsink on it
tantalum capacitor at C2J1 (near the CPU)
I'm wondering what the markings are on each of those parts. I'm missing the mosfet, and the cap at C2J1 is blown and unreadable.

[more detail - TLDR]
6 years ago it worked, but at the time, I decided it had no use and that it's capacitors would be useful elsewhere. I removed all the electrolytic caps and some other components. That was an unusual thing for me to do to a working board, and I regret it now.

I want to restore it to working condition. I recently dug up this board and cleaned it up, repopulated new capacitors, the battery socket, and the speaker. However, I overlooked the fact that a 3pin heatsinked component is still missing.

About 1sec after activating full power (ie not just standby), a tantalum cap blew up. I've read that this isn't unusual for a board that's been sitting for years, so I'm hoping it was the tantalum's own isolated failure and that the board isn't ruined. I've looked and can't find anything else that looks damaged.

The blown tantalum is at the center here. I can't read the markings anymore. I can guess that it's the same as most of the others on the board (226 == 22uF), but if somebody has one of these boards then confirmation would be much appreciated:

At the right you can see that the vertical heatsinked mosfet is missing. I stupidly overlooked that. I'm quite concerned about the correct part number for that piece. I looked in an old bag of salvaged parts and found 2 possibilities. One is marked
BT139F
600E
PHm9944 C7
It's legs are bent in an offset which doesn't match the board, and that 9944 looks like a datecode, which would be too new, so I'm doubting it.

The other 3pin part I found in the old bag is a 7805 linear regulator. I've never seen a 7805 on a PC motherboard, but I suppose it's possible.

The dusty photo below shows the full board before repair. I've highlighted the 2 parts I'm trying to identify.

The smaller photo is a picture I found online of an intact board, it shows the heatsinked part that I'm missing.

I would be very grateful if anybody knows the correct part number for that heatsinked mosfet (or whatever it is). That's the part I'm most worried about. But I'd also appreciate confirmation of the part number on that tantalum cap at C2J1.
Thanks for any help.