You do notice that the prototype Re. 2000 G.A. was being tested in the spring of 1941? Which makes it difficult for it to have any influence on operations in June 1940.
You do realize that "disposable drop tanks" do not get added to aircraft by a snap of the fingers? For example, Germany helped pioneer the development of drop tanks, but did not include them in the design of the Bf 109, until the conversion of the Bf 109E4 in mid 1940, with production of the Bf 109E7 beginning in August. Such modified aircraft have plumbing fitted to transfer the fuel from the tanks to the aircraft fuel system, as well as valves that shut off the lines to the tanks (otherwise when dropped all the fuel would leak out of the plane).Now, flying 50 disassembled Cr.42 to the IEA via Kufra was an impressive feat, but I think I can save all those Kangaroo sorties by expediting the transfer of those planes (28, 38? ...numbers vary by source) by the addition of a disposable drop-tank intended for the trip down there ONLY, instead of whatever complicated re-design was undertaken IRL.
I cannot find much indicating interest on the Italian's part for such development and none of the infrastructure development for developing and producing such tanks.
BTW, the extended range of the Re. 2000 G.A. was a product of fitting additional internal tanks, not external drop tanks, which is the way most air forces thinking went. Development of drop tanks faced opposition from air forces because it was believed the external tanks would add too much drag and weight at take off, defeating the interceptor role of fighter aircraft, which doctrine was accepted almost universally prewar. In that period the quest was for faster and higher-flying bombers that would counter interceptors by being fast and high flying, thus not needing escorts. The minor niche then for long-range fighters was filled by multi-engine heavy fighters like the Bf 110 and P-38. It was wartime development of early warning radar and GCI that made the interceptor more practical, while increased engine power and development of lightweight "paper" drop tanks made long-range escort by single-engine fighters practical.
With a lot more development and production capability, the Germans were able to get a few dozen drop-tank/bomb capable Bf 109 to the front lines a year into the war. I doubt the Italians could match such a performance.As is the basis of all this is a start date of January, I don't think it would be a major problem to get them heading down to the IEA over the Summer. A long as they make it there and are operational by the Fall they will be on hand to counter the first of the Hawker Hurricanes that start showing up in that Theater of operations.