As others commented, it can be hard to click the battery connector back into place. First make sure the bar is not underneath the connector. Then, turning the computer so the connector pins are facing you (LCD hinge end closer to you) can also make it easier to position the connector on top and then click it into place.

The Low Beam bulb is the one next to the side marker:

https://www.paulstravelpictures.com/Volk...

(from https://www.paulstravelpictures.com/Volk...)

Here is a partial disassembly guide for the X100 to remove the top plate:

http://www.bolland.be/blog/2014/06/09/fu...

The X100T screws look similar, between these 2 guides you should be able to figure out the easiest way to partial disassemble the X100T to remove the top plate. Note that in the other directions you still have to remove screws for front and rear shell so that you can move them to access the hidden screws that secure the top plate.

Nick has the right answer- the grooves on the ring will slide into the gap around the camera. I realized this the hard way by glueing the the ring to the display side. Luckily I was able to get it off without totally destroying it.

I did the same thing once, and eventually got it out. Try tweezers, a screwdriver, magnets, holding the MBP on its side so gravity is working with you, etc. Eventually the little bugger will come out, you just have to keep working at it.

I've opened these up many, many times, and by far the easiest method I have found to disengage the front clips is as follows:

Lift up the top case by the rear corners near the hinge, keep lifting so the top case is tilting towards you. You will feel some resistance, but keep lifting and you will hear the clips disengage with a 'snap'. Doing it this way should not bend the top case metal or loosen the spacing between the top case metal and plastic trim. The clips will not break, they will still engage when you put the top case back on.

It basically takes me 5 or 10 seconds to take off the top case now, and the case goes back on nice and tight as before.

YMMV and all that, but that's my experience.

This photo can be slightly misleading if you're not careful. It appears that unlike my cable, the pictured cable has the gray dot on both sides. In this photo you can see the 2 little sideways U notches that should be on the OTHER side. In photo 22 you can see that there are NO such notches as he is sliding the cable out of the connector.

My gray dot is only on the underside (not visible when the cable is plugged in correctly. When I first took the cable out to replace my Airport board, I thought maybe it had been inserted the wrong way which will damage the motherboard. So the gray dots are not a good indicator, just look for the sideways U notches as indicated in the iFixit directions.

There is a steel 'latch' that flips over from the left side of the connector, to the right side. After you flip this latch over, the cable will easily slide out.

I had a logic board replaced by Apple (bad nVidia GPU), and believe it or not the Apple tech mixed up the screws. My latch did not work as good until I discovered and swapped the misplaced screws.