Down this way they usually say that a lot of the teachers who are parents themselves also need to be at home for their kids so as well as blaming transport links many teachers cannot attend anyway.
Take the u bend off and check that's clear, is the sink draining OK? Can't see how a drain smell could be associated with a washing machine in that set-up.
No need for them to attend providing they have all of the necessary information, adequate measurements, wall construction, which walls are load bearing, first floor joists directions etc.
Looks like gable end straps and should not be removed. They should be fixed to the gable end studs and the horizontal boards. If they're not then you should ensure they are.
Watch the video from 1.34: