Hi,
well in that case, you will most likely spend your days slaving behind a bench.
I would guess the percentage of massage rather to 10%.
Physically demanding in MSK is that you work standing up for most of the day and have to get into some awkward positions at times.

As stated above, be prepared that MSK makes up for only a small part of the Physio degree - a bit more if you put Orthopaedics and Trauma into the equation.
We do not lift - transferring patients (if that is what you are thinking of) is a technique that requires skill and practice not so much size or strength.
I have been working for more than 20 years and do not have hand issues, others do. Depends on your work area and the approaches you use.

Gov vs Private - that's about right. Better money in private but far more stress and higher patient per hr ratio. No weekend rota and emergency call outs in private- although, that again increases the income in hospitals. A hospital job gets you to move around a lot more and you work in a team. You will learn what you prefer.
Who knows - maybe after a 3 year degree, if your interest in biomeds persists, you'll end up in Respiratory.

Good luck,
Fyzzio