1. Not at all - in fact I think the best way to do this is to store the values from the text boxes you want in variables which are then used to repopulate the text boxes when you move to a new record.
2. Not clear on what you mean here. You want to be able to search for the latest data related to a customer when you select their unique ID in a combo box? That's possible too - you'd have to create a query to pull back the fields you want, with the Max of customertable.recordnumber where customer ID is the value in the combo box. Easier than it sounds written down