In that scenario where you don't have the required amount of GR (let's just say 0 GR for example), what happens in the order of resolving the individual clauses:
- De Annulos is aced, so that you can search you discard pile for that job that marks a location. Recruitment Drive is found.
- You are at the stage where you're about to play the card, however you lack the GR to play the card. Recruitment drive stays where it is. The dude that Annulos was attached to does not become the leader for the job, since no job was played.
- Since there is no job, and thus this dude isn't the leader, the dude doesn't have +1 bullets and a stud.
All in all, De Annulos goes to Boot Hill, and Recruitment Drive stays in the discard pile. The key thing is that in De Annulos it says to 'Play the card', and in doing so, any cost associated with playing that card (GR for example) must be satisfied first before the card is played. If you're lacking on GR, you can't play the Recruitment Drive.
Kind of in the same way, as if you had 1 GR and you attempted to use a General Store to bring a Legendary Holster into play. Even with the reduction from General Store you're lacking on GR funds, so the General store cannot be used to bring the LH into play, and so the LH stays in your hand.