The Commentary to 1026.2(a)(2) #1 indicates direct personal contacts "...such as follow-up letters, cost estimates for individual consumers or oral or written communications relating to the negotiation of a specific transaction." is not an advertisement. Therefore, this information does not trigger further advertising disclosures.
Additional Comment: If no house has been identified, this loan is not subject to RESPA. Therefore, you should be careful not to issue a GFE. If you do give a GFE, it is not a changed circumstance once a house has been identified.