Rhiellie
First of all welcome to the forum.
You wrote
we will obviously need something fairly powerful
As to equipment you really don't need something powerful as much as something reliable and
IT MUST BE THOROUGHLY CLEANABLE.
Mincer/grinderAny 1-1/4 to 1-1/2 HP motor model will suit your needs. You could probably get away with a 1 HP motor but with the next one up you have the capacity to grow/expand, as you will. You will find that eventually you are buying stewing steaks, chucks etc. and making your own minced beef, beefburger, faggots etc. (the list goes on trust me).
Sausage stufferI would recommend that to start out you purchase one that is about 5 lb capacity that way if you need to make more sausage in the future you simply buy a bigger machine - spreading the outlay over time - and use the smaller capacity machine for test/sample runs as well as for the more unusual sausage combinations - you will start experimenting with all sorts of combinations trust me.
Brining. Smoking and Ham curing will depend on how how much space you have for the Smokehouse, freezer space etc.. Curing hams can take up to 6 months and need to be kept somewhere.
I hope that you find this information of some use to you.
kind regards
Parson Snows
PS if you have any more specific queries please let me know