For the head shape, I don't think the heads of the dwarves are too similar to each other. Panya has rounder features, while Oghram and Horgath have more rugged features.
Fantasy dwarves and real-life people with the condition of dwarfism are two different things. For one thing, "dwarves" refers to fantasy dwarves while "dwarfs" refer to people with dwarfism. Most dwarfs don't look anything at all like fantasy dwarves. That said, I didn't mean to say that there was no standard for the dwarves we created, (All of them are short, have wide proportions, save Lurik pre-redesign, and have a smaller head-to-body ratio) but rather that we didn't want the standard to be decided by another piece of media. I'm sorry for implying otherwise. Dwarves are pretty much the only common fantasy race that doesn't have flexibility in what determines them. If you look at other species, you'll see that media have different interpretations on what defines those species. Orcs in Warhammer are way different than the orcs in Warcraft. Plenty of media has its own interpretations of elves. And dragons are wildly different depending on what region you're in. But dwarves are basically always the same across media. We talked a lot about this and felt that what people consider dwarves often tend to be closeminded, and that we wanted to broader the margin of what can be considered a dwarf. So yes, there is a standard of what dwarves are considered to be in DD, but it's a little looser than the typical mainstream idea of what a fantasy dwarf is.