When are prereqesites checked for Variant Human’s feat?

The steps to generate a character are:

  1. Choose a Race
  2. Choose a Class
  3. Determine Ability Scores

A player choosing Variant Human as race gets a feat in step 1. However many feats have prerequesites that are only fulfilled later in the character creation. Can a player choose these feats as the feat provided by variant human or not?

Examples

  • Spell Sniper requires the character to be able to cast a spell. The earliest point when you get access to a spell as variant human is step 2, provided you choose this feat.
  • Heavy Armor Master requires proficiency in heavy armor, which a fighter gets, but only in step 2.
  • Defensive Duelist requires 13+ Dex, but ability scores are only assigned in step 3.