SFDC Lead to Contact Conversion

Your SFDC set up may be a cause here. Depending on what information is being mapped from lead fields to Contact fields.
Also, is your Marketo form fields being used are not Person Contact fields?

Be carfull not to add person contact fields to your Marketo form, If your form is using person contact fields and not Lead fields, that can be a cause for not converting with all your lead info.

What aboutlist upload? are you mapping to the correct lead fields? have you built up a lot of field aliases and mapping is wrong?

Regading emails, not sure about that without examples of field data.

I am double checking the field mapping in SFDC - that seems to be the issue.  Hopefully, once the fields are mapped corectly that will remedy the problem. 

Thank you for your input! 

In my experience, when a lead is first converted (5-10 minutes) it takes some time to sync over the Interesting Moments and other Marketo info...YMMV.

Whitney, be sure to also consider mapping lead info to Account and Opportunity as well. Depending on how your SFDC is set up, sales may want to see the info there as well. A lot of folks create ghost or "shadow" fields to map information they want to see on multiple objects.