understanding opportunity assignment

Hi, our company craft products for municipalities and local government, and we're trying VTE to substitute our in-house-made intranet app;
we will be glad to hear your voice about this practical issue:
- say there is a call for public contract where is foreseen some products that we craft;
- suppose that two person JOHN (from company ONE) and MARY (from company TWO), both partecipating for that call, send us two emails about a price request the products required in the public contract;
- last, suppose JOHN and his company never contact us before, MARY and her company are already our customers.

In that case, could anyone suggest best practices:
- should we assign the JOHN's email to a new Lead (JOHN) or a new Contact (JOHN)?

- should we assign the MARY's email to a new Lead MARY) or the already existing Contact (MARY) or the already existing company (TWO)?

- in both cases, should we assign email to new Opportunity (PUBLIC CONTRACT) too, or is it not necessary?

- if JOHN or MARY send us further emails, are that automatically assigned to same entity as the previous received, or should we assign them manually?

Many, many thanks for every suggestion !
Graziano

Hi Graziano,
may be:
- public call -> this could be a CAMPAIN in the CRM
- MARY and JOHN send you a price request -> the module that allow you to manage sales request is POTENTIAL, so you have to create in CRM two POTENTIALS related to the CAMPAIN and to ACCOUNT
- MARY and JOHN they should be CONTACTS of two different Account, you have to insert them as Contact/Account because you can not create Potentials related to Lead
- the emails should be related to the Potentials via Webmail
bye