Fantastic graphics Andy.
I still haven't had a chance to sit down and read the Endeavour series properly, but as someone who is currently working out how many planets he can get away with giving Alpha Centauri (you can't just make stuff up nowadays when we have to cope with actual found actual exoplanets!) this is relevant to my interests regardless.
It was fun to make up.
Fornax and Alaz have, as a matter of fact, some pedigree already.
Alpha Centauri Bb was reported in 2012 as close to Earth mass with an orbit of about 3.25 days - but, sadly, further investigation demonstrated that the evidence presented wasn't robust enough to pull out of the signal noise. Fornax may still exist, but the evidence for its existence was way short of statistical significance.
Alpha Centauri Bc is more robust - Dumory et al reported (via the transit method) a probably planet at around 0.1 au from Alpha Centauri B, with an orbital period somewhere around 12 days (as high as 20 and as low as 8), so that one made it in and Alaz is probably still there.
The rest of the planets come from that and resonance with the orbit of Alpha Centauri A and B around their common scentre of mass - the gas giants (Taranis for Alpha Centauri B, and Tian for Alpha Centauri A) are, as anyone geeky enough will have spotted, in orbits such that they can end up always "behind" their parent star during the period of closest approach between the stars. The other planetary orbits in each system come from resonance with the dominant planet's orbit. That provides for a long-term stable system (as any proto-planets in other orbits wouldn't have survived over the aeons)
The second gas giant in the Alpha Centauri A system (not yet shown), Enki, is far too close to its star to have evolved there, but the double star system provides plenty of opportunities for such orbital shifts. In fact, having seen systems like TRAPPIST-1, it's arguable that this system is too plausible to be realistic...