Hi geo... Creating seperate footways 
higway-footway footway=sidewalk is possible.. but the routing does'nt work if you dont create connections wit other roads.
It's also possoble to embed the tagging in the highway with footway=right left or both.

The hoogstraat and the marijkestraat are product of duplicated tagging. Drawing roads on roads?
The routing will not work.
Crossing roads without a node will not route. 
Greetz,
eggie