In an attempt to be helpful, I thought maybe I should offer some of my Sonic scans from my US Dreamcast Magazine collection. I have the entire run of the publication (with all the demo discs), thanks to an old family friend, and a long time ago, I scanned the Sonic centric portions. Note, the size of the pages caused some issues in digital transfer, but I tried my best to keep the information present. In the scans, you will find some info on "Sonic Adventure", such as an Emblem checklist, a blurb about the VMU Chao Adventure, the basic rundown of the game, and a pretty decent explanation of the original Chao AI. "Sonic Shuffle", such as an announcement and a review. Cute little art for the announcement, too. "Sonic Adventure 2" predictions, and first look. The magazine was canceled before they could properly review the game. There's even beta images, like Sonic without the Soap Shoes Advertisements for the Sonic OVA and "Sonic Adventure", some plushies, and even a blurb about "Sonic Underground"! Interview with Yuji Naka Basically, all the pages with Sonic I could find in the entire run... which actually is less than you'd expect. I pretty much inspected all issues and this is what I got. Some I've seen scans of on the site before, but I have yet to see any of the more obscure pages. Would this be useful to your site?
So it seems that the Sonic OVA was available for rental on August 10, 1999 in USA, similar to how it was also available for rental in Japan on January 26, 1996.
It's great you've made the effort, but we're well beyond the days of single page magazine scans. We're in the business of preserving entire issues, not least because in this case, Sega Retro exists. But also http://retrocdn.net/Category:Official_Dreamcast_Magazine_%28US%29_scans we've got a full set. Not that there isn't room for better scans, but... yeah. And when we have a full scan on Retro CDN we can do this and suddenly we're amazing.