They are spread out and are on all floors. I did a not so scientific search of doors with two peek holes. From the lobby take the hallway behind the front desk. I found many HA rooms but when I went the other side pass Simba's child care I found none.
1) Yes, they are spread-out.
2) Some are close, others are actually pretty far away.
3) They cannot make them all in convenient locations.
4) Tough to say it, but Disney and ADA provide ACCESS not EXCESS.