Welcome and thanks for your question!
First, let's talk about your personal
1) FBAR (Foreign Bank Account Reporting) requirements using form
TDF 90-22.1 As you mention, the filing
threshold is $10,000 at any point during the year. Note that if you have multiple accounts that the $10,000 is calculated based on the total in all your accounts and not a per account basis.
2) Form 8938
(Statement of Foreign Financial Assets
) - the filing threshold for this is $50,000 in assets at the end of the tax year or $75,000 at any time throughout the year. Its definitions of foreign assets are more comprehensive than that of the TDF 90-22.1,so depending on the value of the stock of your Hong Kong company, you may need to complete this form. Here's a good summary
of what's a reportable asset for Form 8938 and TDF-90.22.1. If required, this form is submitted as part of your 1040 tax return
reporting on a US tax return - any income to you personally derived from the Hong Kong business must be reported on your personal tax
return. Remember that you can take a credit
on your 1040 for any Chinese (or other foreign) taxes you personally pay.
Second, you mentioned your wife is concerned about U.S. tax implications on the income. Amounts paid to a foreign corporation and not into your personal account are the corporation's income, not yours personally. You do not need to report this business income on your personal 1040.
Please let me know if you need clarification on any of the above points and I will gladly assist you. If not, then please give this answer a positive rating. Thank you and have a wonderful day.