As far as I know there are no replacement parts simply for sale. Replacing with similar parts from another machine seems the cheapest way to deal with the problem; however excercising your power as a consumer and simply buying another brand coffeemaker may work out better in the long run for you. Sorry I couldn't be of more help.

I am unfortunately unaware of the answer to this question. I hope someone else can answer it.

That is indeed the question. Because of planned obsolescence companies basically assume you will just buy an entirely new coffee maker. My best suggestion is to buy a similar model at a thrift store like Goodwill and use the parts from that.

Well firstly make sure the valve is pointing the right direction in the rubber tubing. As for your question about pumping water, that I can't answer. Try soaking the valve in alcohol then warm soapy water, there may be residue from the grinds on the ball causing it to stick.

Your best course of action might be to go to a thrift store and look for a similar model by Mr. Coffee and simply replace the valve. Drilling the hole initially might have thwarted additional attempts to make this valve work.

Unfortunately no. Because a lot of things are built with planned obsolescence in mind, it's very difficult to find parts. I would check thrift stores for same brand cheap coffee makers that might have similar equipment.