All Disney busses can handle at least 2 ECVs or standard wheel chairs. If for some reason the tie downs are broken or missing, or the seats wont lock in the up position,the bus may have a reduced capacity. In some cases, the bus may not be able to handle any.In that case, the handicapped sticker is pulled from the bus until the issue is resolved.
There are some of the new busses, that may be able to handle 3.Theres was also 2 busses, that could handle 5, but they are held for large groups traveling together.If they are still on property. Those 2 busses, 2716 and 2717, are probably almost 30 years old, but had really low mileage on them.The other busses in that same series, have over a million and most have been retired.