A and C
The reference to the drinks spill is far-fetched and I wasn't promoting it as being likely as I am sure you were not.
Experience tells me that the aircraft had big electrical issues
This is probable, but without further evidence the cause could still be terrorism or a defect. The only thing that is looking unlikely is pilot error.
There is no way to rule out a bomb causing damage to the electrical system or even explosive decompression. The time frame for the ACARS messages, abrupt end to the messages, and lack of voice communication all suggest that things went wrong very quickly.
Somebody with an in depth knowledge of the electrical system may be able to shed further light. For instance, a localized electrical fault (even with fire) is unlikely to take out multiple systems in a very short space of time unless they were physically or electrically close. That would suggest a wider more dramatic issue at play.
Prior to the loss of communication the pilots presumably were not aware of a serious problem.