Azers are on pages 158 and 159 of Savage Species. 6 racial levels, gets a hit die (with skill points, BAB, & saves) at 1st and 3rd. 1st-level is +2 Con, -2 Cha, darkvision, subtypes, +2 natural armor, and a feat. Gains other Azer racial traits as they advance in the racial class. After completing all 6 levels in it, they can/must move on to normal character classes.
Merfolk have 1 HD and a +1 Level Adjustment, but no Savage Species progression (probably fine to start them off in a 1st-level party anyway, they'll fall in line after the rest of the group reaches 2nd-level). Flamebrother salamanders are on pages 168 and 169, with 7 racial levels, gaining a hit die (etc.) at 1st, 2nd, and 5th-level in their racial class. Initially +2 Int, +2 Wis, small, darkvision, fire subtype, and minor versions of their normal monster qualities. Other salamander types are not listed in Savage Species. Tritons are on page 199 with a 5-level racial class, getting a hit die at 1st, 2nd, and 4th. They start with the water subtype, +2 Str, +2 Con, darkvision, and a few other minor traits.