Today guided me through a workaround to the 'junos-show-version-interrogation' error (thank you Dimitris!). It's not a fix, but it did allow me to add my Cisco device and move forward. The workaround was to drop his cisco_ios_show_version.ind script into /usr/share/indeni-collector/kb/parsers/cisco/ios (we added the /cisco/ios) and restart the collector. This (somehow) short-circuited the junos interrogation failure and allowed indeni to add the device.
As we talked it through, the best guess as to the cause of the junos-show-version-interrogation failure was that it was expecting an XML response from the Cisco router, but receiving text, and then erroring out, hence the "Failed to parse XML" error message. I haven't yet tried to run this script in isolation, but I will, hopefully tomorrow -- at least for my own learning. I'm sortof guessing that someone has already fixed this issue in a more recent version of the script -- otherwise it feels like more people should be running into this error? I'll try to find out.