The chinese version was created first, then the international one on indiegogo, and then from independent sellers who may be selling either the Chinese or English versions. It is the BUYERS' responsibility to deal with whatever they end up buying. My car's Multi-Functional Display/navigation is in Japanese, even though it's sold in so many different countries around the world in different languages, the company will not send me a firmware to update it to English/multiple languages. The only way that I can change it is to buy another MFD ($2899). I don't think the H1 is going to be that difficult and expensive, but it will take some working around and creativity.
As for firmware, if you have the international version, then wait for XGIMI to post official firmwares on their website. That would be the best and safest way. Unless there is a known issue that everyone is getting then I wouldn't worry about anything.
I had the pleasure yesterday to compare a Chinese version with an international version, as far as I can tell the only difference is the prefix of the serial number (Chinese starts with CH (or CN, forgot) and International is different) everything else is the same right down to the model number. I think it's obvious that they are the exact same product just different customizations of Android. I would be ok with this if it was their own OS but it's not they are using an Open Source code OS and hacking it to artificially limit it, that's what is really grinding my gears, I like to support companies that support good business practices but all the development for the International version was already there, they didn't include Googles GApps so they didn't have to pay additional royalties on the "International" version as far as the OS is considered. It COULD have been sold as a single unit allowing different language options and configurations based on region as the International one does since its already built into the OS, my quick analysis of the China versions shows how much the Android OS has been hacked and components removed for not other reason than to restrict the capability of an Open Source OS, right down to limiting what Apps can be Sideloaded!! (Not sure if this is a whitelist/blacklist limitation or something else but I'll find out soon enough as I already bypassed it. Anyway. I have no doubt when I figure out how to clone the Firmware I will be able to move it to the China version. Also I have a sneaking suspicion that the China version sends an abnormal amount of Data to China, I'm not sure for what but my homelab network monitoring tools were shouting bloody murder. I'll look into this further when I have time, if anyone wants's to collaborate PM me (Will probably start a thread in XDA).
Your last point is valid. Will keep personal attacks out of this.
On the international and Chinese version is one and the same firmware as the difference is that in the international version is activated to support other languages and in China there. The Russian was able to activate this feature. But there must be very careful otherwise you may damage the device ..