Tordanik
(Tobias Knerr)
3
Sadly, I’m not aware of any OSM-based routing engine which already offers proper indoor routing support.
For tagging, I tend to recommend using the Simple Indoor Tagging schema. (With the obligatory disclaimer that I was involved in writing it.) The highway=corridor tag isn’t really a fully thought-out solution for indoor mapping in my opinion.
And yes, using SIT would mean that you need to convert polygons into a routing graph. Which isn’t that hard, conceptually, but none of the routers you mentioned comes with that feature built-in.