謝謝回複,還有點不清楚，麻煩你再看一下

How does USCIS decide to give me a I94 with H1B or not? Is it purely by chance?
For question 2, 3, 4, do you mean that only after I get a H1B visa first with current H1B, then do transfer or renew, I may have chance to get 3 years extension? Or you mean, if I am lucky, I can get a H1B with I94, and if I am lucky enough, I can get H1B for three years with I94?
Thanks for your answer.
It seems to be no rule to follow. May just go ahead to use EAD.