The current status on the A300/A310 is as follows:
Still in service, due to be retired at the end of April. The acft currently plies the LCA/ATH runs 4x weekly as well as the 2x weekly PEW (Peshawar) flights.
Retired at the end of March
Was supposed to be retired in April but Emirates have decided to hang on to this acft a little longer. Due to Peshawar apt being unable to handle A330s they are going to have to keep this acft to continue serving this route. I think for the month of April this acft has been withdrawn from service for maintenance (outside chance they may repaint into the billboard Emirates titles). It will re-enter service in May and do the 4x weekly daylight frequencies into LGW plus the 2x weekly PEW frequencies. I understand this acft will be withdrawn from service and returned to Airbus at the end of September 2002.
As for the question on narrowbodies, i think Qatar's answer explains most of the reasoning. A couple of additional points:
-certain routes have good cargo demand, and this is also an important revenue earner for the airline, so often the widebodies are needed for their higher cargo capacity
-aeropolitical constraints are limiting addition of extra freqs esp. to Saudi Arabia. Therefore, with the limited frequencies, and the strong demand, Emirates can easily fill widebodies. eg. to JED, and soon to RUH they operate 434 seat B777-300 (two class config) and they fill them up.
-going fwd you are likely to see Emirates deploy more A330s across the Gulf runs and raise the frequencies. You see as Emirates expands its other connection banks ie. the morning bank to Asia, the 777s will be required there and thus can be pulled from the Gulf routes. However, the Saudi routes, ie. JED and RUH will continue to see 777s due to the frequency limits.