1. Is it true that an atomic clock will run faster at a higher altitude where gravity is weaker?
Yes, relative to a clock at a lower altitude.

2. Would time slow down almost to a stop as one approaches infinitesimally close to a black hole event horizon?
Yes, from the point of view of somebody much further away.

3. If time slows down near a black hole, then from a vantage point very near a black hole event horizon wouldn't the rate of infalling matter increase, since the universe further away is not affected by time dilation?
Yes. As an object passes through the event horizon, all of the light in future history, violet shifted into gamma rays, strikes the object destroying it utterly.

4. At the event horizon, wouldn't all the matter in the whole universe get sucked into the black hole, and the size of the black hole expand to fill the universe, maybe become a new universe?
No. From a large distance, the gravitational field is completely normal and unremarkable. It is just the same as a star of the same mass.

5. Wouldn't all the matter getting pulled into the event horizon be length contracted, and therefore accumulate into a thin massive shell as the whole shebang gained mass and the event horizon moved outwards?
No answer.

6. Don't massive shells exert zero net gravitational force on objects inside them?
Correct.

7. At the instant the event horizon is crossed, assuming one survived, wouldn't one then find oneself inside a large empty space?
One would find oneself bombarded by a vast influx of gamma radiation, frying one to cinders.

8. Wouldn't Hawking radiation be emitted into this empty space?
Good question.

9. Wouldn't radiation emitted by the event horizon be highly redshifted, since the event horizon increased in radius at such a huge rate?
Yes.

10. Isn't a black hole a black body emitter?
Yes.

11. Could this Hawking radiation be shifted into the microwave spectrum, if viewed from the inside?
I don't know if there is any inside.

12. Could we be inside a black hole now?
God question.

13. Could the cosmic microwave background be redshifted Hawking radiation, essentially an image of the inside of the event horizon?
Good question.

14. Black holes begin as supernovae, with only 6-15 solar masses. Could Hawking radiation from accreted matter outside the black hole, have led to baryogenesis inside the black hole?
Run that one by me again.

15. Could these questions form a more complete cosmological model?
Questions do not form a model, but can lead to one.

16. Should I be nominated for a nobel prize? :-)
Not yet. You need to ANSWER questions, not just ask them.