Welcome to the slippery orange slope! You have already figured out one thing - be ready to buy so you can move quickly when you see something that you love!
Brides de Gala is indeed one of the classic H scarf designs. I am not a true fan, so to me it feels like it is reissued about every 20 minutes! But, as LadyBaga pointed out, the reissue is not the same. Sometimes the design is tweaked, the colors are pretty much always different, or it may be the same pattern but in a different format. (For example, a design is originally 90 cm, but in a subsequent season is done in different colors and in a 140 cm.)
I believe that the CDC pattern that you got is a re-issue - the original did not have the border with all of those cute dog pix. The Zambezi scarf is also a re-issue, I haven’t looked at it super closely as I have the one I wanted, but in that scarf the design is the same as the original, but the colorations are different. I believe that the Zambezi in black this season is actually the same colors as the original black, though I didn’t look super closely to confirm. If that is true, then it is the first time that I can recall that happening.
Three Graces has not yet been re-issued as a 90 cm scarf, but it has been made in several formats. So there is a 90 cm, a 140 cm and, I believe, a gavroche, which is a 45 cm. If you see one of those that you love, I would grab it now. The artist behind Three Graces, Alice Shirley is relatively new to the H world, but she is immensely popular and has designed a scarf per season, for the last few seasons.
We are just about on top of the start of a new scarf season - there are 2 per year. Keep an out for the thread for the A/W 2021 season and you can see how the process works. If you have the time, you can browse through the threads for other seasons, though they tend to be very large threads...
Sorry this is TMI!!