I dont think it would have altered the outcome of the war. The Doolittle raid accomplished nothing but as a moral booster and a punch right back at the Japanese. It was never intended to cause lots of destruction only as to let the Japanese know that they were coming for them. So if the Doolittle raid had not happened, oh well.
Yes Midway would have been lost and Australia threatened however the biggest thing it would have caused for the Japanese was buy them more time and prolong the war. The Japanese could not have invaded the mainland United States. It was too far of a distance to be able to logistically sustain an invasion force. It would have taken too long for the Japanese to get reinforcements to the United States and then at some point there forces would have become to spread out and would have been easy to defeat them. The main thing it would have been to hard to resupply and reinforce an invasion force over 6000 miles.
As for the Carrier situation. The United States had the recources to build new Carriers very quickly througout the west coast and the east coast. Between 1941 and 1945 alone the United States built 102 Aircraft carriers of Different types.
Large Fleet Carriers
Midway Class - 3 Ships (137 aircraft each)
Essex Class - 24 ships (103 aircraft each)
Light Fleet Carriers
Siapan Class - 2 Ships (48 aircraft each)
Independence Class - 7 Ships (45 aircraft each)
Commencement Bay Class - 19 Ships (34 aircraft each)
Casablanca Class - 37 Ships (30 aircraft each)
Bouge Class - 10 Ships (21 aircraft each)
The United States was able to build these carriers very fast to replace sunk ones, something the Japanese did not have the luxury to do. For instance CVB-41 Midway was laid down in October 1943 and completed March 20, 1945, CV-9 Essex was laid down 28 April 1941 and completed July 31, 1942. That is just barely over a year for the Essex. All of these carriers were built throughout the United States from the Philadelphia Naval Yard to Norfolk to San Diego. There were so many places to build them that the Japanese could not have stopped it.
Basically what I am trying to say is that had the Carriers been at Pearl Harbour all it may have done was delay the outcome of the war. Nothing more.