De Havilland Hornet used as escort fighter for RAF & 8th USAAF

The Hornet was developed from the Mosquito as a single seat version but arrived very late in the war.

1) What if the Hornet is somehow developed alongside it's sibling the Mosquito allowing it to enter service in 1941?
2)What if the RAF seeing it's performance start to use it as a long range escort fighter also with drop tanks allowing 'Heavies' to attack targets in daytime over Europe including Germany?
3)How well would the Hornet perform in this role?
4) If the Hornet performed well with the RAF would this interest the USAAF, allowing them to use it and not wait until the introduction of the P-51D to escort their heavies thus lowering their loss rate and causing an earlier destruction of the Luftwaffe?

Would any of this be plausible?
Did Winkle Brown visit you in the night? The Hornet was his favourite aircraft and he used to perform aerobatics, at air shows, on one engine with it. It is nicer to fly than a P-38.
To clarify, the Hornet was not developed from the Mosquito but was an entirely fresh design, drawn around two of the slimline Merlins developed by Rolls Royce. It did draw on experience gained with Mosquito and could not have been designed alongside as A : Mosquito proved De Havilland was right, and B: the two stage Merlin wasn't ready in '41 and the later slimline version wasn't even a glint in RR's eyes at that point. In addition, the epoxy resin adhesives used to bond the wooden and metal components together, as well as the duramold moulding technology hadn't been developed then.

It might not even have happened, as Geoffrey De Havilland didn't think they had the capacity, what with development work on Mosquito, the scaled up Sabre engined DH 101/102, and the Spider Crab (Vampire) all ongoing at the same time.
It came as early as it could and the first deliveries were taking place as Germany collapsed. Had the war gone on, I'm sure they would have seen combat to the Luftwaffe's chagrin. They were shitting themselves over the Mosquito, Hornet could well have outgrown their over rated jets.
What about a pre-war Royal Navy requirement for a long range/ long endurance twin engine multi-role heavy fighter/attack aircraft with cannons and capable of dropping bombs or torpedoes and DeHaviland looks at the DH88 Comet and goes 'how can we beef this up?"

Instead of the Fairy Fulmar and Blackburn Roc?

How well do you think they'd done especially in the Med and the Malta convoys?
Instead of the Fairy Fulmar and Blackburn Roc?

How well do you think they'd done especially in the Med and the Malta convoys?
Something like the Roc was 6000lbs empty to 8000lbs gross weight. The Sea Hornet was nearly twice the weight at 11,000lbs empty and 16,000lbs gross weight. A Fulmar is 7000 and 9000lbs.

The Westland Whirlwind was 8000 and 10000lbs, only a bit heavier than the Fulmar and first flew in 1938. Perhaps a blend of Sea Hornet's wing on a Whirlwind's body, a carrier aircraft needs a slow landing approach.

With twin Merlins such a plane will be even heavier but with 4 cannons and high speed it would certainly out perform the Fulmar. You should be able to find room for the navigator/observer that the RN liked and could probably carry 2 500lb bombs but probably not a torpedo. The good piece of kit would be the cannons for both air and surface targets.

With good range they would be able to strike targets well inland from their carriers and the carriers would be able to eliminate bombers from their airgroups. The Whirlwind could even do dive bombing.
As far as I recall, IOTL the Hornet never ended up facing any air to air opposition. Sure, it was plenty fast, well armed and had a good range. But we can debate all day how it would perform against a swarm of intercepting Focke Wulfs and Messerschmitts.
Probably quite well. From wiki - Captain Eric "Winkle" Brown, former fighter pilot and officer of the Fleet Air Arm, was one of the world's most accomplished test pilots and he held the record for flying the greatest number of aircraft types.

Just after VE Day the first semi-naval Sea Hornet PX 212 arrived at the RAE, Farnborough. Eric Brown initiated "work-up to deck-landing" trials. 37 years later, he was still impressed:

"In level flight the Sea Hornet's stability about all axes was just satisfactory, characteristic, of course, of a good day interceptor fighter. Its stalling characteristics were innocuous, with a fair amount of elevator buffeting and aileron twitching preceding the actual stall"...

"For aerobatics the Sea Hornet was absolute bliss. The excess of power was such that manoeuvres in the vertical plane can only be described as rocket-like. Even with one propeller feathered the Hornet could loop with the best single-engine fighter, and its aerodynamic cleanliness was such that I delighted in its demonstration by diving with both engines at full bore and feathering both propellers before pulling up into a loop!"

"Circumstances had conspired against the Sea Hornet in obtaining the recognition that it justly deserved as a truly outstanding my book the Sea Hornet ranks second to none for harmony of control, performance characteristics and, perhaps most important, in inspiring confidence in its pilot. For sheer exhilarating flying enjoyment, no aircraft has ever made a deeper impression on me than did this outstanding filly from the de Havilland stable."