in my opinion, if the stern tube is dodgy, you have no choice but haul and block now. To do anything else is to risk total loss of the boat. If the tube separates suddenly, it can let in an enormous amount of water in a short time, overwhelming your bilge pump. And even if it doesn't, sooner or later the bilge pump is going to fail for some reason. Maybe a piece of trash gets caught in the float switch, or the marina power is out overnight and the battery dies.
That having been said, if it IS the tube, a temp. kludge to slow the leaking is to pack the tube from the outside with modelling clay while you're short-hauled. This will slow or stop the leaking, but will leave the engine/prop unusable. This might hold you until your January haulout. But you lose use of the boat between then and now so why not haul out for the winter now?
If, on the other hand, your tube and hose are in reasonable shape, your proposed actions look good, with one addition. Be sure to dig out the old packing and replace it with new packing of the correct size. Your old packing is probably shot, accounting for that leak, and the compression nut is probably bottomed-out, which accounts for the whole assembly turning.