Choose electrolyte for electroplating
There are two issues here:

First, you will be oxidizing water. You would end up making oxygen in most of those cases, before oxidizing your metal and making the cation you need. 

Second, even in cases where your metal will oxidize before water, the concentration of the metal cation in the solution will be low and variable. This will create problems with controlling rates of deposition and uniformity of deposition.

That is why the electroplating baths rely on the already dissolved cation and not the metal as the source. This way you have lots of the cation you need in the solution to work with and you can put some inert counter electrode.