Audio feedback killer/audio delay circuit/bucket brigade circuit
... it seems that the minimum standards for this type of circuit, is a delay of approximately .015-.02ms.



The speed of sound is 340 m/s at standard temperature and pressure. 
Sound will travel 5.1 mm in 0.015 ms. 


Move your loudspeaker 5 mm further away from the microphone and you'll have the same result without the complexity of further electronics.

Maybe there's something wrong with your research?




  [From OP's comment:] "I can tell you that simply moving one of my pieces 5mm is not going to fix the problem." 


The trouble is that that's all your 0.015 ms delay is going to do - it will make it seem that the speaker is 5 mm further away. You won't cure feedback - you're making a reverberation unit. You're missing some basic physics understanding somewhere along the way.

Your link to Audio delay using discrete components is a question about generating an audio delay so it's not clear why you think this will assist you with feedback reduction. 

See what information you can find on constructive and destructive interference of sound waves. You will find that at certain frequencies and distances the sound will interfere constructively enhancing possibility of feedback whereas at others it will cause destructive interference reducing feedback.

Another area worth looking at is noise cancelling microphones.