1) yes but it is not easy, sometimes you pull the motor mounting bolts.
2) yes, use a socket the size of the top piece holding the retainer. Place a shop rag under the head and smack the socket quick, one or both retainers will fall out; Getting them back in is another story..........
3) ignore the slotted end on the rocker shaft, it is not threaded. There are 2 appx. 6mm long pins (something like that) that have to pull out of the head, then you can twist the shaft back and forth, WD 40 them and pull them out. Some are very stubborn. You will break the head casting if not careful. The manual shows how to grind and remove those pins also.
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country