Amazing! Funnily enough, I had a pony from each of those collections on that first page (aside from the rainbow curls). There's a photo of me unboxing Posey Rose on my third birthday (which was in 1991) soooo that tracks. Pony Bride was big in Oz - almost everyone I knew as a kid had one. Secret Surprises too - I can remember about two or three friends who had those ponies, plus Eyelash princesses.
I knew about a lot of the ponies in that 1988 catalogue (only had Seashore, who I inherited from my sister, who's 4 years older than me) from various bits of merch but I don't recall them being as widespread; of course, that's probably because I was a little younger, so the early 90s ponies loom larger in my mind.
Anyway obviously that's all anecdotal... some great finds!