As a start, I've banged the Mossie numbers into a spreadsheet, which, as you can tell from the other tab, I started after one of Neil's previous posts about RAF strength.
For the record, I believe this actually underestimates total Mosquito strength in Australia. The Bankstown factory had by then produced 61 airframes, in addition to which about 74 UK-built T.IIIs, PRXVIs and FB.VIs were transferred to Australia, though a very few of these may have been transferred post-April '45. The transfers noted on the document are B.IVs, and are almost certainly the "Highball" bouncing-bomb aircraft of the former 618 Squadron. So there's a gap of around 130 Mossies in Australia, which for obvious reasons weren't under direct RAF command.
It also under-states Canadian Mosquitos. By April '45 Downsview had produced 789 Mosquitos, however the document only accounts for 451. Many of the dH Canada Mossies were retained in-country for the RCAF, or were awaiting transfer. So another 300 or so.
The document also does not account for the Mosquitos on strength with the USAAF - 25th BG, 492nd BG, 416th NFS IIRC.
Bottom line for mossies is, by my reckoning, a good deal more than 3,281 Mosquitos on Allied strength by the end of April '45. Call it 3,700 for argument's sake, though I suspect it's a touch higher. Total production to that point was 5,746 from all factories. To have 2/3 of all produced airframes still somewhere in the Allied Forces is a quite staggering accomplishment after the long years of war.
I confess I'm a touch reluctant to add other types - the numbers are hard to line up, and I was able to do the Mosquito numbers based on their context. I knew which numbers to assign to which row based on my (rather sad) awareness of the Mosquito story. Mossie XIXs in India make sense to me, Mossie XVIIIs do not. I can't say the same about the various marks of Spitfire or Hurricane.
View attachment Strength.zip