1) I have some areas marked as winter dry - This is either because the winter westerlies can't reach these areas due to rain shadow, or, the winter high pressure system deflects the winds away from the interior. Does this seem reasonable?
Probably, although at that latitude, considering the axial tilt, maybe D climates should be more common? Of course it depend on hotter the world is.
Alone, the larger tilt mean colder winter, and C climates are less common since they require fairly mild winters (above freezing point).
It could be really dry in winter if we consider Asia or Africa for reference. The f climate would stick to the coast but barely, it''s mostly the climate of the island that are further away from the continent. Having a dry winter is not so bad for the vegetation since dry summers actually have a bigger impact in comparison.

2) The ITCZ reaches quite far, but I think there will be a minor rain shadow effect, and it is also biased to the east, so the interior is quite arid. Would there likely to be a desert here? Bearing in mind axial tilt is greater, and the world's average temperature is also a few degrees hotter.
I'm not sure because in summer at least, the moisture comes from the north and the south, so maybe not that dry.