I was actually thinking that Italian East Africa would be likelier to stay Italian than would Libya.
There was no census carried out in AOI between 1936 and 1941. However, the population of European origin in 1938 was assessed between 150,000 and 200,000 (this excludes the military, and does not take into accont the temporary migrants - another 200,000 between 1934 and 1938 - who in any case were completely repatriated in 1938/39, once the road infrastructures were completed). The native population was also not censed, but the estimate was around 12 million. Therefore, the Italian settles were somehow around the 2% mark. This makes a lot of sense, given the short time available IOTL for the emigration, as well as the Italian difficulties in paying for the Abyssinian war, the infrastructures which were needed in Lybia and AOI, the intervention in Spain and the re-armament: by 1938, the original vision of AOI as a settlers colony had been shelved, and the development of economy was given to large companies, most of the times in a monopolistic environment. [if anyone is interested, this is a good and very well documented essay on Italian emigration toward AOI http://www.ilcornodafrica.it/rds-01emigrazione.pdf - unfortunately it's in Italian]East Africa didn't have a huge number of Italian settlers, though (something like 30% of the population in OTL). Nor was it considered a region of Italy instead of a colony. If there's even more Italian immigration after the discovery of oil, and the maturity of a generation of Italians born in Libya, the attachment will get even stronger, and Libyan independence that much harder.
I believe that an Italy who managed to navigate WW2 and prosper might again look at AOI as a settlers colony, but the numbers could never become significant (at best, 5% of the population). Besides the huge cost involved and the lgistic problem of turning AOI into a settlers colony, there are other areas where Italian manpower will be required in very significant numbers: Lybia, Albania and the Balkans, the economic boom and full industrialisation).
Numbers in Lybia are quite similar in 1938 (20,000 colonists settled in 1938) but IMHO Lybia is going to be quite different: indigenous population is below 1 million, logistic issues can be managed much more easily, the oil industry is going to start soon after the end of WW2, and will require skilled manpower both for the oil industry and the port and road infrastructures, but will also boost the demand for foodstuff, and increase the momentum for settlers to be relocated to Lybia. I would anticipate an Italian presence in Lybia around 30-40% of the population by 1960.
Actually it was Addis Ababa. The duce wanted a completely new city (or better cities: European, coptic and muslim) to be the capital of the new Italian empire. There were a lot of studies carried out, and ultimately a very attractive town plan was redacted. Then war came, and everything was shelved (but IIRC that south-africans made use of these plans later on)Hadn't Mussolini ordered the building of Asmara to be a monument to Italian fascism? Why build such a thing in a less important Italian colony?