re: They can only control the orientation if the gyros hold out
But the USA would be responsible for any damages or injuries from reentry thus we will want control of Hubble at reentry. There are several parts of HST that could survive reentry and would hurt people. To prevent this we need to attach a booster or some means of control to the HST before reentry.
If this is the case then we can just as well repair and boost it maybe with a reentry module attached.