Hi,
I did my biometrics recently (July) and I was also worried because they had a difficulty to obtain my fingerprints during the appointment. Only 2 of my fingers were green and the rest had orange/yellow warning. However, 8 days after the biometrics I got update on my I-485 form that my interview is ready to be scheduled. This mean that my fingerprints were sufficient for the FBI background check. I never received any update on I-765 or I-131 forms that fingerprints were taken.
In worst case, you will get a second invite for fingerprints. If even after the second appointment, they will not get sufficient fingerprints, you will normally moved forward in the process to interview and you will be later on asked to provide police clearance from places were you lived in last 5 years.