Tarrasque (by the way, if you want to do internet search for the mythological beast, use only one 'r': tarasque, the true spelling) is ta-rask. Don't accentuate any syllable. Pronounce both 'a' as in "father". And try to pronounce the 'r' (I've trouble telling the difference between a "w" and a "r" when pronounced by an American).
Bulette, with its -ette suffix, looks like a French word -- but it ain't one. -et(te), means "little one" (fille, fillette for little girl, for example) -- a bit like the -ling of English, as in darling. That would make a bulette a little "bul". Really don't know where the word comes from. (Bullette, with two "l", could have meant little bubble, or bubbling, but that don't describe accurately the creature.

) I'll say it's pronounced bulett -- not bulay, neither bulettee.
Ixitxachitl is harder than it looks, because it use that weird "aztec"spelling. But actually, the "x" are pronounced "sh"; the "a" as in "father"; the "ch" is pronounced "k"; and the "tl" is pronounced "tel" (or "tle", in English).
So, write it
ishitshakitel, and it's already less of a tongue-twister. Ee-shit-shah-kittle.
Anyway, I'm totally sure for the pronounciation of tarrasque (I ought too

), quite sure for that of Ixitxachitl, and less so for bulette.