yes and no..... is it possible yes, is it recommended no...as a general rule, your primary fermentor should be 2x the batch size to prevent must from bubbling up into your airlock/blow off tube. growler as a secondary and for bulk aging would be ok though
That's right and wrong at the same time......
The justification for using a larger container i.e. 1 gallon batch in a 2 gallon bucket, is to do with having a greater surface area, so if you do use ingredients where it's possible that you'll get either a lot of foaming, or a possible eruption when stirring/aerating, then you are entirely correct.
But, at the same time, a lot of us will still use a 1 gallon glass jug with no problems/ill effects etc. You just have to be more conscientious with your method, and of course, if you make exactly a gallon at start, after racking for best result, you have to work out how you're gonna top up to remove any airspace caused by racking losses.
Lots of people will make a batch of JAO in a glass jug, but only filling it about 3/4's of the way up once the fruit, honey and spices etc are in it, then after maybe a week, once the ferment has settled down, fill it up to just below the bung (inch or so) and let it finish.
It's much more aesthetically pleasing to see a nice glass jug bubbling away in the kitchen, than the more practical bucket........
And
here's a link to the gotmead JAO thread. Oskaar posted the recipe on the second post, first page - and while it's a mammoth thread to read, it does answer most of the questions that a new mead maker might have about it......