I have these things
I have the Specialized Tahoe shoe and the Shimano platform/clipless pedal that you mentioned. The shoe is very comfortable but the sole is not particularly stiff, in fact I think my light walk/hike shoes have a stiffer sole. Also, be aware that once you install the cleat on the shoe it will make contact with sidewalks, tile floors, wood floors etc. so it's not always appropriate to wear even though easy to walk in. As for the pedals, I like them. Easy entry and exit with the clips and if you want to use the platform temporarily that works well too. IF you want them 100% for the platform be prepared that they are not as grippy as pedals made specifically to be platforms so your foot can slide off. I think the pedals are heavy, but there's nothing I can do about that.
2010 Specialized Sirrus Comp (XS)
2010 daVinci Global Venture