What is happening in dreams is often a representation of what you think dreams will be. The whole thing is labeled as "lucid dreams" in your mind, and when you become lucid a whole host of new schema and ideas come into play. Things like "unstable" is because it doesn't seem like a stable thing, to be in a dream a dream and aware or that you think awareness is somehow a paradox of being inside a dream, so you don't think it works. Your dream characters being nothing more than NPCs with little or no programmed codes shows what you think of the dream in t respect. That the dream couldn't come up with a lifelike version of it, or that it is them, but it really isn't them and you pull up nothing. Not summoning the right thing could be your thinking that the dream is random, or that you have no control over what you summon. Change your mind and you change the dream.

Usually this is actually done by people hitting a random amount of that seem to make them "now able to have emotions in dreams without making it unstable" or "summoning enough items that you have leveled up your item leveling system to be able to summon what you want"

However you think it works can often be how it works when it comes to your brain. Here is a thread I made about dream control, I believe that dream control and stabilization are the same mechanism.
http://www.dreamviews.com/dream-cont...ur-dreams.html