Yes those exercises are great. Choosing to start on machines is no bad thing. Are they superior to free weights? Depends which side of the fence you are on. I have spent years using free weights to develop strenght for rugby with the occassional machine thrown in as a change (squat to leg press, BBrow to machine row etc).
Deciding to change your life for the better and deciding to dedicate a few weeks to machine work to allow yourself to get comfortable with the gym environment using exercises were the resistance and plain of motion is fixed is a very sensible option.
Advising you to jump into free weights and all their complexities etc first thing could be a winning idea, but as iv seen before it can be daunting and could scare some people off.
The idea of a trainer is a good one, if you have the spare cash and dont mind someone watching you train and scrutinising your work (as a pt I can say that.
Let us know what you decide.
It isn't the mountains ahead that wear you out....Its the grain of sand in your shoe.