Can you give grades and text feedback to students for an in-class written exam? This was possible using the Postem tool in Sulis, is there an equivalent tool in Brightspace?

There isn't an exact equivalent to Postem, but there is a workaround. Group Locker or the assignment feedback function.  See this link for a list of sulis tools and equivalent tools on Brightspace. https://www.ul.ie/brightspace/articles/sulis-to-brightspace-tools