We gave our best but it seems we won't be able to solve this one out with 100% certainty
The date 14 October 1944 can be found in the excellent book of Mikhail Bykov about Soviet aces and seeing the sources he used on the end of the book, I have no doubt that the date is the right one.
I still think that Houghton could be the only possible candidate. He is still missing and we don't know where he crashed. Mann is buried in France. If he was found in Yugoslavia, he would have been probably buried in Belgrade War Cemetry. However, he could have been buried in Budapest War Cemetry as well?! It would be very helpful if we would see the data about his recovery and burial post war.
It is possible that Shadrin overestimated the success of his attack, but still, the whole event occurred very close to Soviet base, so it wouldn't have been hard to find the wreckage and confirm the claim, and its nationality.
There was only one Bf 109 unit operating in the area, namely 3./NAGr.2 and it did lose an Bf109G-8 to enemy action during October 1944, but when and where I don't know. An "recce Bf 109G-6" was reputedly forced to land at Gabrovnica airfield in Bulgaria by 31.IAP on 3 October (according to memoirs of Mikhail Tsykin) or 10 October (according to memoirs of Nikolai Skoromochov) and the pilot who forced it down was Tsykin. interestingly enough, Bykov does not list this claim in his book, in Tsykin biography.
Cheers,
Boris