When Flatland was written, was the satire as evident as it is now, or did readers actually think Abbott was serious about his views on class, women, etc.?
There was mixed reaction, and some people were frankly confused about the author's intent. This is one reason for the editor's comments in the preface to the second edition, also written by Abbott.
In Flatland, would time be considered the third dimension?
By some flat Einstein, yes, probably. Tims certainly acts like a dimension, and it seems convenient to list it right after all the ones you are using up to describe your space. So yes, if you said to A Square "I came from the third dimension," he might say, "But that's time, isn't it?" and then you'd have to explain that time is -a- third dimension but not -the-third dimension, and so on.
With what did Flatlanders "feel" when they were feeling one another to determine the other's shape? Did they feel with their angles, or with one of their sides?
It isn't totally clear. I think that one of the vertices would be more sensitive as a tactile organ than a flat side. Different writers and filmmakers have had various interpretations about the interaction of figures. We'll see some examples later.