What you posted is one person's opinion of the sound of the Dream 90. He is no more an expert than you or I. He says that he thinks the Dream 90 sounds "somewhere in between a regular single coil and a P-90". No...it sounds like a P-90 because it is a P-90. There are lots of P-90s that have different sounds from each other, but they are still their own thing.
Yes, the Dream 90 sounds more like a single coil than the Mean 90 because it is designed to sound brighter with less midrange than the Mean 90. (A Pearly Gates also sounds more like a single coil than an Invader).
The size of the bobbin has very little to do with the sound of the pup. If it did, the SD Lil'59 would sound like a single coil pup. Not even close.
The main influence on the sound (comparing a single coil with a P-90) is that the single coil has the poles, as the magnets, within a single coil of wire, and the P-90 has nickel poles within a single coil of wire, and dual opposing flat bar magnets. (Of course, a humbucker, even the Lil'59, has steel poles between the two coils, and one flat bar magnet beneath the poles).
Like I said, and as you can see in the pics you posted, the Dream has one coil with the poles inside that coil, and two flat bar mags. If the Dream were just the same but the bobbins were wider, it would sound exactly the same.
The popular opinion on hbsized p90s is that they are not actual p90s. They fall short due to the bobbin size and shape. Now, some builders shave the bobbin down to fit inside an hb cover, and those could be considered a p90.
Anything that has another type or sized bobbin/form factor are p90 styled, or built like a p90. I have a set of harmonic design vintage plus that are steel poled and have dual magnets. They are wound to 5k. Their s90 is like 12 to 15k and has adjustable poles on top of that. That is very p90 like, but again, not a p90.
the MIM strat pickups from the 90s were built the same way. Steel poles and dual mags. Nobody ever accused them of sounding or being a p90, even though they are constructed like one.
You are getting hung up on semantics I think. Just because someone says it's a p90, doesn't make it so. You need to have a soapbar look with the wide, flat coil, and the dual mags to be one.
P90s can have non adjustable poles too.
staple pickups are not p90s, even though they look like it.
G&l pickups are built just like p90s as well. Nobody calls them p90s though.
anything that doesn't have the coils shape and dual mags can only be p90 style.
Coil shape is a big factor in how a pickup sounds.
It's why a tele and a strat pickup wound with the same wire to the same spec sound very different as well.
the stagmag is technically a humbucker, but is basically 2 single coils on a humbucker plate, and sounds just like that, not a PAF by any stretch.