IPad – Destroying iPad Mini 1

Being "cheap Chinese crap" it probably has a generic Bluetooth name like "Bluetooth Keyboard" and maybe has a generic hardware identifier, too. The iPad (or pretty much any computer) can get confused when paired with two different devices that do not distinguish themselves and you might have some conflicting remnant of pairing with another device. So try deleting all the bluetooth parings in your iPad mini and then re-pair this keyboard.

In situation as you described, HDD could survive with high probability, but as MBP retina uses SSD instead there is a small, but chance to kill it. First steps to repair it is to disconnect the battery and disconnect the SSD. This is guarantee to prevent:
1) future information losses
2) future damage of logic board.

What damages can you expect - generally, in these cases this is 50/50 game. Cleaning requires disassembly of the MacBook and wiping board with cleaning agent e.g. ethyl alcohol (96% concentrated). It is non-conductor, so then when macbook will be reassembled, it probably will work.
My friend had similar problem: water and MBP retina 13. And now his MBPr works OK, but only with power cord plugged in. I do not recommend connect it to power cord until it properly dried and cleaned (with alcohol).