Many thanks Helio, for those calculations.
Looking at #18, and this is a key whether or not it needs slight modification, it seems that at least Jupiter would be in the HZ. There is some variation, but the highest figure I have seen (above) for our Sun is 2AU diameter; thus 1 AU would have the Sun just reaching Earth (current) orbit.
Oddly, I don't see how they got to those distances.
If you bump the Sun to 1AU in radius, it will have a much larger surface area by a factor of about 46,200x what it is now. That's a whopping amount of radiation!
But, when it gets that large, it will be cooler. So if we use, say 3500K, then the ratio difference with the Sun is 0.61. The radiation, however, will be reduced by the 4th power of this difference, so eqch square meter of its surface will only be 13% as bright as the Sun's, but then multiply this by 46,500x more sq. meters than today's Sun.
This gives a luminosity that is 6,250x greater than today.
Since radiation decreases by the inverse square law, then we can simply take the square root of this to get the distance to match the effective radiation at 1 AU, which equates to 79. Meaning we would have to be at 79 AU to match what we have today.
The fact that at 3500K produces more in the IR likely will reduce that 79 AU but not in half, no doubt. So what am I missing?