G'Day JoJo and a warm welcome to the forums. How are those Falcons going these days? 😉
The "tingling" you mention has been an issue on both Mac notebooks and other brands for quite a few years. I first ran into it on an early model PB12, and I've seen it occurring even with iBooks, when a metal component has been touched.
THe problem can almost invariably be overcome on any notebook computer by using an earthed power adaptor. In the case of the MBP this means using the 3 pin power cord, rather than the two pin "duck-head" plug adaptor. It first happened to me, though, while working in a donga in outback Queensland where it turned out that the building wiring itself was faulty, lacking an earth, so if you do find it continues after switching to the "3 pin" power cord it is probably time to call in the local "sparky".
You will find a long thread on the matter
here and discussion of the same issue in a variety of notebook brands
here.
As far as the bottom case goes, I've seen a few reports of this here. In a couple of situations , at least, it has been reported as being fixed by taking the computer to an Apple Authorised Repair centre or Apple Store, where the bottom has been removed and a stay of some kind adjusted or clicked back into position.
Cheers
Rod