Questions about the USSR and China under Mao

My own knowledge on communism and how it was practiced by the USSR and Mao's China is severely lacking, but I work with a colleague who had some questions (most of them familiar, but I don't personally know the answer) and I said I'd ask some folks who'd know better; his questions were:

1. Did people all have the exact same salary regardless of job?

2. In positions that were similar and worked in close proximity, for example nurses and doctors, what were the differences in their salary if they had different salaries according to job? Even if a doctor made more than a nurse, was it noticeably so or only minorly? Were these salaries comparable to American salaries?

3. If a colleague was completely lazy and did no work, did he get paid a salary, and in the same amount as hard working colleagues?

4. I told him that under Mao, landlords were given the option of handing over their lands/apartments/additional housing and were executed if they refused. Was this accurate or was I mistaken? I'd read something here I think that said as much, or perhaps saw a youtube video about it but I thought I'd get a concrete answer to take back to him.

5. He was saying that without a profit incentive, people won't innovate; what innovations from the USSR and Mao's China could I point to? I remembered some major stuff later on myself that were released for free and brought no profit to their creator, for example linux, but forgot to mention it at the time.

6. Could someone start a business if he had an idea he wanted to pursue. I told him the government would own the business and himself and the other people working at the company would be government employees, but not sure how true this is.

7. I told him people like farmers were effectively government employees and the produce they grew was owned by the government and rationed to the people, again, not sure how strictly true this is.

8. If a person didn't want to work at all, just stay home and do nothing at all, what does the government do about it? Does he still have housing, medical care, payment to care for his family and himself, and a salary?

9. Why did China begin to transition away from the communism it practiced?

Could you folks also please give me references to the answers to provide him with?