Fire as such can cross a Ward; its consuming telos is too broad to be shut out as a “weapon.” You could chuck a flaming tree across a Ward.
On the other hand, a hollowed-out metal sphere containing naphtha (or other wrought incendiary devices) would be a weapon and would burst against the Ward rather than getting through.
Absolutely – and your engagement with them can determine whether they withdraw into a narrow Westriding-plus-Rim yeoman nationalism that feels betrayed by and alienated from the coastal elite, or hold to a broader Shayardene identity.