Lindsay,

You definitely want to scan your photos into your document, then hand the entire camera-ready project to the printer/copy pro. If you give the printer your photos, he/she will only have to scan them in him/herself, which the printer will charge you for.

And as for your second question, it's up to you, but I do final reminders in the form of a postcard so I don't have to worry about envelopes. They add another step to the mailing process that I don't want to deal with unless I have to. If you use a postcard, be certain to print/copy it on card stock (heavy weight paper of 90 or 110 lb.) so that it will stand up to the trip through the mail without ripping.

I hope that helps. Good luck!