You could just use a new piece of hose on the actuator and suck on it yourself to produce vacuum, it doesn't need a lot and you'll see it work.
Could the turbo fail? Absolutely. Been there before too. But since (here) turbochargers cost $1400 each and fitting is about $350, it's an expensive exercise and it's just good practice to eliminate the other things first because they're not going to cost you a lot to check.
I'd hate to be the one to say to someone "Yeah mate, replace the turbo" only to find out it was a $2 piece of hose, so we go through the cheap stuff first and through a process of elimination we find the problem.
It's just bloody slow on a forum. If you were in my driveway we'd have done all of these things within the first hour of the first day and probably have replaced the turbocharger and the left hand windscreen wiper blade already.