For 1:
Unless your footnotes have paragraphs that shouldn't terminate in a punctuation mark, you should be able to use -
Find = ([!.\?\!])(^13)
Replace = \1.\2

For 2:
For empty footnote paragraphs, except where the footnote ends with an empty paragraph, you should be able to use -
Find = (^13){2,}
Replace = ^p

Because you can't replace the final paragraph break in a footnote or endnote, there is a limit to what can be achieved via Find/Replace. A macro, however, could be used to iterate through each footnote and do the required processing.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]