Question about changelings and substitution levels

[ATHATH]

Can a changeling with the racial emulation feat (as their level 1 starting feat) take a non-changeling racial substitution level (like, say, Elven Wizard 1) as their first level, or do they have to wait until level 2 to do that?

[Kelb_Panthera]

Been a while but IIRC class choice comes before everything else in the leveling process so you can't choose a class unless you meet the qualifications on the level prior or earlier. You'd have to wait for level 2.

[Doctor Despair]

Humanoids, when they take their first hitdie, then immediately exchange it for their first class level. As such, you can be a changeling with 1 humanoid hitdie and select Racial Emulation as your starting feat. Then, you exchange the hitdie for your first class level -- which may, indeed, be a racial substitution level (or, also notable, a racial paragon class).