2. Your separate property houses. If community property fund was used to pay for mortgage or repair, then community must be reimbursed, which she is entitled to half of the reimbursement. This would not change the character of the house.
3. If your pre-marital money is not kept in a separate account, and more than likely is commingled with community property assets, then it becomes community property, unless you have evidence to trace the amount and origin of each and every single transaction. Otherwise, she is entitled to half.
4. What she said does not matter, unless you have a writing to prove it.
5. These invoices cannot be used as evidence. For one, they are hearsay. Two, you have no proof she was paid for. You have responsibility to find out her assets. You could hire a private investigator.
6. She lives in china, meaning she cannot file a divorce in California. She could file in china and you have to go back to china to defend. For your benefit, it is easier to file in California since your assets are here and you are here too.
7. It depends on what you meant by separation. In California, if you lived separately and you formed an intent to get divorce, then that date is important such that everything you earn afterward will be your separate property and she is not entitled to anything. However, if she owes debts, regardless whether it is community debt, her separate debt, your separate property will be responsible.
8. If you can wait, wait. You will avoid the headache of going through embassy channels for service of process. It is also easier to get an agreement while she is here.
9. This is up to you.