I was thinking of a 10-20w solar panel on amazon connected to a 10A PWM Solar charge controller that has a dual USB port connected but not using a redundant 3.5Ah battery and that's connected to a 10000mah power bank that's connected to a USB powered fan. What do you think?
Hmmm that seems like a lot but you could always give it a shot. Personally I try to go with a KISS policy (Keep It Simple ya Silly goose). However that solar setup may seem simple to you, if that's the case give it a shot.
Just run your hand over the wire and make sure there are no sharp spots. Then like you said have spots for them to get off the wire and you should be good. That's not to say it won't happen just a lot less likely.