Solidus sent Ocelot to Shadow Moses to steal Metal Gear? What else did Solidus set up?

He pretty much set up the entire thing! He was hoping to use REX as a weapon and I presume leverage over the Patriots. Because of that plan failing, he was forced to resign because of him losing the trust of the Patriots and the people of the US over the whole Genome army which went against his public belief that he was against eugenics.

So Ocelot set out to do this for him while also being a spy for the Patriots? So Ocelot is against Solidus all along right. Did Ocelot really try to steal Rex though? Well in reality he sold the formula which is why other countries have their own in MGS2, so I'm guessing he just made off with the "blueprints"

Well, it's kind of confusing. Solidus was hoping Ocelot would actually steal it. Ocelot being the Patriot spy that he is, knew this wouldn't be good for him. So he pretty much double-crossed Solidus by not stealing it. To answer your second question, yes, he was against Solidus all along. And he was only sent in there to get the blueprints, test data, and to find out everything he could about it.