You can't stop follow in a macro. You need to use some kind of movement key. I usually hit my "spread out" key, for instance.

There are a lot of different systems for targeting. Probaby the simplest is to set focus on all of your clones to your main, then use a macro like this to cast offensive spells:

Code:
/cast [harm,nodead][target=focustarget,harm,nodead] SpellName
See the stickies for more info.