I have a general question regarding citing in footnotes and the formatting. In some cases the page number is separated from the "p." when there is not enough space and latex forces a wordwrap. So "author (year), p." are on one line and the page number on the following line. Would a "protected blank" be a solution to this problem?
If you write
biblatex does all the things for you. It inserts the command
\ppspace between the automatically inserted "p." and the "12". By default
\addnbspace (a non-breaking space), so you won't get a line break there.
If you use another citation package that does not do this sort of thing automatically for you, consider just using