6. it’s hard to say based on your account. Frankly I don’t care a jot whether a watchmaker wanted to buy my watch. How does that impact their ability as a watchmaker? Also, you’ve no idea of any other factors influencing why they aren’t buying right now.
Re the estimate, that’s standard practice, quick over view, winds like gravel, our standard service charge for this type of watch is €x but to get a detailed assessment they need to open it up. Most places are unlikely to drop everything for you and start opening watches there and then (unless perhaps you have an existing relationship).
For the clasp, if they’re an Omega service centre, as far as I know, they can’t go bastardising your bracelet adding random parts from others references. They can only look on the extranet and offer you what’s available. For vintage that is generally, absolutely nothing or perhaps a moderns replacement.