Thanks, I think a big part of what's interesting about fantasy universes is the alien mindsets, both of humans living in fantasy worlds and of non-human races. Depicting Dwarves as cranky bearded humans would be a huge missed opportunity, and even though Mathilde has been getting on really well with Dwarves, she's also quite aware that they're entirely different to people, and she's still going to get caught out here and there by it.
One interesting thing one of the 2nd Edition Roleplay books picks up and runs with is how strongly the Empire, particularly the southern provinces, were influenced by the dwarves.
It's easy to forget that the Empire was formed largely as a dwarven uplift project.
Before the dwarves intervened, the pre-Empire tribes were pre-literate Bronze Age pastoralists who didn't make permanent year-round settlements (although they did have winter dwellings). After the dwarves had finished teaching the early Empire they were literate, steel making city dwelling agriculturalists. (As an aside, that's why it's noted in a couple of places that many of the Reikspeil words for crafting, particularly those related to stone or metal, are Khazalid loanwords.)
That was all a long time ago, but contact and cultural influence has continued. Tome of Salvation mentions that dwarven style ancestor worship is standard in the southern Empire, amongst other adoption of dwarven customs.
As a result, Mathilde's regional cultural background should be particularly compatible with the dwarves, as she'll share many unspoken assumptions - even if they are manifested differently due to different psychology, and there should be a deep implicit understanding of dwarven nature that has been assimilated into her cultural heritage after thousands of years of continual contact. Dwarven psychology may be different, but it won't be alien, it will have been explained to her through children's stories and folk tales and similar all her life, particularly considering that there's a decent sized minority population of Imperial dwarves who have immigrated to live in the Empire.