My partner recently had some water damage to her MacBook (A1425), rendering it completely unresponsive. It turns out her backups were not working either.

On the Macbook, nothing happens when pressing the power button, trickery with shift + ctrl + power doesn't help, it seems completely dead. When the charger is connected no light appears on the charger. So I think it's safe to assume it is an ex-mac; it has seized to be. However, the files are of some importance.

When researching online, it seems there are two possible options. One is to try to get hold of a thunderbolt cable and booting it in target mode while connected to another Mac; the other is to buy a hard drive enclosure, remove the hard drive and put it inside, and access from another computer.

From what I've read, the latter is my best bet. First, it might be cheaper than buying a thunderbolt cable; second, it doesn't depend on as many components inside the Mac not being damaged; third, it would leave us with an external hard drive.

However, this leaves me with a few questions, as I am not great with computers and especially illiterate with Macs.

1. How can I know if an enclosure is compatible with the hard drive?

2. It seems to me this model has two hard drives. Would the same enclosure work on both, or do I need to get two different ones?

3. I am not a great tech mechanic, but I did successfully change the battery of a glued together android phone once, and I used to change the parts of desktop computers back in the day. Would hard drive removal be trivial?

4. Once removed and in the enclosure, are files encrypted? How could they be accessed from another computer, and would such access only work from another Mac? I use Linux, it would be useful to know if I need to borrow a Mac to retrieve the files.

Sorry for the lengthy call for tech support, and thank you in advance for any help!

Edit: Thank you all so much for the amazing help!

For anyone who might arrive from searching the Internet:
The main lesson might be to be careful when buying an external box for the hard drive of these generations of Macbooks. The hard drive used in the 2012 Macbook Pro with retina is different from the one used in the Macbook air, regular Macbook, or regular Mac from the same year, and different from SSDs used in the end of 2013 and onwards. If your Macbook is from 2013, count the pins.

I ended up buying the OWC Envoy Pro s suggested by @bobsuruncle as I found it available with relatively short shipping time to where I am in Europe; Sintech also has a model that might be a little cheaper. External boxes for these hard drives don't come cheap, unfortunately.