According to a seminar I attended a Treasury check cannot be held if the endorseor is the payable too name. But here is what Reg. CC says:

(2) A check drawn on the Treasury of the United States that is not governed by the availability requirements of Sec. 229.10(c);

Can this be held 7 days?

You are quoting sec. 229.12(b)(2) -- it's helpful to know the context of such quotes -- which allows you to delay availability of non-qualified next-day checks until the 2nd business day. Such would be the case if the Treasury check is deposited by someone who is not a payee on the check.

Whether or not you can hold funds from such a check until the 7th BD will depend on whether you have circumstances allowing you to place an exception hold on the check. Assuming you have a Treasury check deposited by other than a payee, and the account is a new account, it won't be subject to the requirement that the first $5000 be available the next business day (it's not a next-day check), and could be held for whatever period your new account disclosures say.

The redeposited check hold would clearly not apply, but in addition to the new account exception, you could use the repeating overdraft, large deposit, and, in some situations, reasonable doubt exception reasons to impose an exception hold and delay availability until the 7th BD.

If a new customer, less than 30 days, deposits a Treasury Check payable to him, in person, less than $5,000, can we put a new account hold on this deposit? (9 days) I thought next days items that met the above listed criteria, couldn't be held longer than the next day.
There are so many new compliance issues, I'm confusing myself right and left.

You could not put a new account hold on such a check. If the check were more than $5,000, you could hold the excess over $5,000 until the ninth business day.