No. What you are looking at are three completely different machines with dedicated functions. You will find that 99% of what you want to do will be with the straight lockstitch machine. A Serger, what you call a hemmer, has one purpose and one purpose only, which is to cut and edge fabric. That machine would be an extreme luxury. You could probably get away with a home serger, but again, an extreme luxury for someone starting out. My suggestion on the other specialty machine is to farm the work out until you find out if you even need the capability of such a machine.
No one lives forever, the trick is creating something that will.