Looking for very obscure Japanese Sonic art and/or calendar

So I've been on mostly an unsuccessful search for a series of art created very early on in the history of the franchise, almost certainly created before Sonic 2. It's extremely obscure and falls outside of most people's knowledge of early Sonic media and only seems to exist in a few places. The artwork can be seen in a severely cropped manner in a few old British magazines, including CVG and Look-In magazine, and can be seen here, where they are termed the "Sonic Holiday Scenes". I've been aware of these images for years and have been trying to look for them without being covered up.

I've been mostly unsuccessful, except for this Twitter post. Here we can see part of one of the backgrounds that is covered up in the magazines and shows several characters unseen so far. Apparently, this image comes from a 1992 Japanese calendar, and thus it may have some of the other images. As the Tweet says, these images are likely not scanned onto the internet in unobscured form, but we don't know for sure. They could be floating around some website disused since 1998 for all we know.

I really want to find these backgrounds in all their glory, because they have to exist somewhere. Apparently, there's a Japanese calendar that had them, but that's all I know besides their presence in the forgotten magazines. I have no idea who in particular made them and at exactly what time they were made or released. If anyone knows a good place to look for these artworks or knows someone useful to ask, please do so. I've been obsessed with the little I've seen of these for years as they show so much old JP stuff!