I got all three eggs and hatched them (although I'm currently leaving the Matrix dragon as a baby in my Inventory)
I got a 2nd Pyre egg (souvenir).
I got a 2nd Ultramarine egg (hatched it for 2nd Matrix dragon, also in Inventory).
I was not able to get any more eggs (Ultramarine or Sparkling souvenir eggs) despite 60+ adventures. Like you, after getting the 2nd Pyre egg, I never got a "full" message for it.
I don't know if there was a behind-the-scenes egg limit (3 original + 2 duplicates) implemented, but I may just didn't do enough quests.
I'd love to hear if anyone got the 3 Dragons + 3 Souvenir eggs, but would understand them not mentioning it to avoid criticism from folks who got only 1, 2 or zero eggs.
Notes:
- I'm maxed on Pyre Crystals. 100/100. (I already spent 100 to hatch my Pyre egg/Flare Dragon..., so I've earned over 200 Pyre Crystals)
- I'm maxed on Dragon Scales. 99/99
- I'm maxed on forever snow. 60/60 - (The Exchange Trade is still open since I haven't fed my Maxtrix Dragon x2)
- I'll be maxed soon for Lapis Lazuli stones. 17/20 (I'm just waiting on a Deep Sea Adventure.., and the quest is still open for same reason as above.)
- I have the ability to purchase an Ultramarine Egg in my Magic Forge for 250 gems..., and can propably keep cranking out Matrix Dragons as long as I buy Ultramarine Eggs at 250 gems each).
Additional note: the Pyre message posted earlier in the main thread (Hi North!) came from a 2nd account.