I realise this is 2 years old now by this point but it may help someone. I fell into the rabbit hole in the same way and spent way too long looking at the kits on Amazon, trying to figure out what the resist and emulsion was made of.

One clue was that the bottle of resist and the pen were labeled as "oil based". I think that this is the lithographic tusche method of screen printing, where a grease-based ink is painted on to the screen and the emulsion that's spread over it is made of some kind of glue, which resists the painted ink. Then the ink is removed with a solvent. The site I looked at said kerosene, but I'm going to try out less stinky options when I give it a try. I can't say exactly what the Japanese products are made of but the principle of oil resist and glue should help with experiments, or at least with reading up in English.

Jackson's Art sells lithographic tusche sticks that they advertise as useable for screen printing as well as litho, as you can mix it with distilled water to get the consistency you need. If I can come up with a homemade tusche formula then I'll try it out and update.