Disclaimer: I don't bug my beer, so this is not coming from experience but reasoned conjecture and corroboration by sources.
As far as sanitation goes, Brett is as easy to kill as regular brewers yeast. Jess Caudill, microbiologist and brewer at Wyeast, wrote
"[Brett] is as easy to kill as any Saccharomyces cerevisiae strain of yeast. No crazy chemical cocktails are necessary... just your normal alkaline cleaning and acid sanitization. It's up to you if you want different equipment for your wild brews."
As to the bacteria, they have higher temperature tolerances, but can also be killed (mostly) by Starsan or completely by Iodophor (and bleach but not recommended.)
The main problem isn't so much the sanitizer, since iodine will kill everything it touches, but organisms being harbored in scratches and hard to sanitize areas. If a small amount of S. cerivisiae is left in a keg or fermentor, it does not real harm. Cross contamination of a small amount of a different strain of yeast will not make any noticeable difference to the beer. A contamination from the other microbes may also not initially make a huge difference either, but given enough time, such as in the bottle, they will have time to propagate and consume sugars not fermented by the regular yeast, causing overcarbonation and potential bottle bombs.
If you are particularly careful cleaning the keg after using it to store buggy beer (e.g. dismantle and soak entirely in iodophor) then you will be fine - there will be no bugs left in the keg. But you're probably best not doing this with anything that is plastic, since that's almost impossible to make sterile due to porosity and susceptibility to scratches.