Who has the right to perform the Salaah

Q:

  1. List the circumstances under which an Imam who is the most knowledgeable may in his own presence permit a man of lesser knowlege to be Imam for that Salaah; meaning that how is it possible for an Aalim to permit a hafiz to be Imam when the more knowledgeable person has the responsibility by virtue of his greater knowledge to correctly be the appropriate Imam?
  2. Does the Imaamat of the unappointed Imaam, despite it being out of place, does the Salaah of such an Imaam and that of those musallees following such an unappointed Imaam, become an invalid or null and void Salaah?

Makeshift Salaah facility

Q: Our work has a makeshift prayer room with a toilet and hand basin in it - is this acceptable? The room is alongside the female toilets and a meeting room and noises carry through the wall into the prayer room - is this a problem? I use a disabled toilet close to the prayer room (10 metres) and have used a plastic bottle for cleansing. The company has taken the bottle away as they say it is a safety problem. I suggested they instal a hand held bidet (like a shower hose) to remove safety problem.  But they want me to use another disabled toilet that is further away (more than 50 metres and through many doors) because they don't want to upset disabled people. How far away should cleansing be from the prayer room?