Just a quick update: I have been carefully checking the fuel tank and have not seen any suction whatsoever since the first fuel-up. I will continue checking it and will have my wrench double check those hoses asap.
I have also had absolutely no decel popping since installing the PC5, which is excellent!
The crickets are fine, don't mind them at all, and when I twist the throttle they add a whole new layer of roar to the engine. I will like them even more, I think, when I get the jards on and have a big brutal exhaust note to go with them.
Thanks to everyone for your exceptionally helpful answers, particularly with the gas tank suction question!