[Neru]

I've only tried this with Note 1- bought used smashed Nexus 7 for the battery (it was cheaper this way) and took the battery out. The battery did fit... kind of. The casing would not close completely. I did use it like that for a year or so, it was fine.
That said, I see you're mentioning thread for Max 2, which is 7.5mm thickness.
Note 2 is 7.1mm.
Note 1 6.8- which does not close completely.
Perhaps it might? I would highly suggest, if you already have the device open to try and measure how thick the battery could you fit inside. Perhaps even if it fits it might be a tight fit.
About direct replacement- I did buy Boox battery from aliexpress before, it did expand after a few months. Because of that I understand not trusting Boox'es batteries, seeing all those dead batteries in their previous support forums.
If you have time, there's tablet search in GSM arena, I guess you could search for a thin tablet with simlar battery capacity, see if that battery is for sale, check its sizing and etc.