No, your DP will not popup on hers. These settings are stored per account (.NET passport).
If you don't log your conversations there's no way they can know what you've talked about. The logging options are: In MSNM - tools > options > messages ... "automaticly keep a history of my conversations" and in Plus - Plus > preferences > logging ... "automaticly log all my chats by default" (you can encrypt those if you still wish to log: plus > preferences > privacy protection > passwords).
Edit: you're welcome
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