Think of it like a game of poker You wouldn’t show part of your hand before the end of the game. If you want your bid to be a knockout bid , then wait until others have shown their hand. If you bid first then someone else bids your knock out bid is likely going to need to be higher than going in strong with your first bid.
Yes they can. List of shareholders is a public document if held as certificate. Parts of that were transferred when broker accounts were formed. You are a shareholder and they need to be able to contact you.