They are custom builds in each case (and a few more). Built by the master Martin down in Oz (tho he no longer builds commissions I'm afraid).
In the case of the 4MT for example, its got 2 x 23mm speakers in the tender, fully sealed with composites, and runs from a Loksound 3.5 decoder with 12 functions. The loco and tender are reinforced to reduce vibration and full prototypical lights and firebox flicker added. (syncronized with the coal shoveling sounds)
Speakers are in the tenders, and a two pin plug links tender with loco, some models have speakers in both the tenders and the loco itself, where space allowed
Smoke is a Seuthe #22 generator, managed by a micro relay controller by one function on the decoder (reduces any risk of the smoke gen overheating / running dry and overloading the decoder
In operations, the smoke gen needs a top up roughly every 10 minutes.
In each case, the 'donor' was the current gen Bachmann or Hornby super detailed model. In the A4, there is a speaker both in the tender (a 40x20mm) and the loco directly over the cylinders (23mm). In all the locos lead has also been added to push the weight up by at least 100g.