No state can repay its debt by selling its bitcoin assets. That sounds funny to me. Bitcoin is already a danger to the states. In addition, if a state has too many bitcoins, the value of the bitcoin is likely to fall.
Nope, there is no correlation. A State can do the same things any other whale: It can hold unto them thus reducing circulation and increasing price, burn them (lose the wallet keys) provoking the same, or sell/auction them which could temporarily cause a cheaper price giving opportunity to some to buy cheap and then price goes back to its natural place.
This is no fiat. Even is the State tries buying bitcoin, it can only increase its price until they run out of money. So this will never happen. And if they sell them, they will eventually run out of them and put it in private hands who could keep/lose/sell them the same.
Suppose the US gov acquires lots of Bitcoin, either by buy or confiscation. You seem to believe this would somehow impact bitcoin's price negatively, when it might actually do the opposite or nothing at all.
Just because a gov gets bitcoin it doesn't affect the value for everybody else. EVEN if this gov is hostile to it (ie. China).