"Whales" are market participants, same as any one else buying or selling BTC. They simply have more resources than the smaller traders who refer to them as "whales".
Miners are market participants, same as any one else selling BTC. They can choose to sell - or not sell - their BTC, same as any one else.
yes but the resources they have is what regulate how the market will behave, they can theoretically drive the price in one direction or another
by deploying fake walls, there is an easy trick that is done with bot on trading that can determine an increase in value without actually selling or buying any coin
They can influence other traders, for a limited time. They can't create demand (or supply) out of nothing. A large trader, wanting to buy cheap BTC, could sell a fairly large amount of BTC, wait for naive traders to panic, and then attempt to buy BTC at a cheaper price. But this isn't a one-way operation - it relies on two parties, the "whale" and naive traders. The same applies if the "whale" creates an ask wall (or bid) wall - if it works, it works because some traders have been influenced, for a limited time (as long as the large trader can keep the wall intact, if that).
The market regulates itself - it finds an equilibrium through trade. If a big trader successfully pushes the price down, the price either rises again - or the lower price is the correct price. The panic from a sudden dump only lasts so long: sooner or later an increasing number of panic-struck traders realise that, apart from that one dump, nothing much has changed, and they switch from bearish to bullish, or at least neutral.
Incidentally, all traders have influence on other traders - every time we complete a trade it feeds into the overall feeling of the market. It's simply that larger traders tend to have a larger influence. But that's all they have - they can't force people to sell them cheap coins.