I don't think releasing them of without the use of force would kill the host. In Naruto's case, it is a simple matter of opening the seal which would release Kurama's chakra and let him leave the host body.

In terms of being controlled by the Sharingan when outside, the hypnosis seems to be a kind of genjutsu which I don't see why it can't be dispelled like a regular genjutsu when working with a partner who can jolt you out of it by providing a chakra burst in to your system. As for the summons, if you can't control the beast then I don't think the summon is going to be useful for you.

Besides, a summon would indicate a contract which if the Kyuubi doesn't want can't be useful given that it seems the only Kyuubi agreed to the contract was under genjutsu/by force.

I don't recall it being said that a jinchuuriki enhances the power of the bijuu, do you have a reference for that?

It seems to me that this isn't even actually full beast mode but a weaker form. Remember Naruto only has access to half Kyuubi's chakara and perhaps if he had it all he would be able to transform in to the full solid beast. Bee, who has also taken control of Hachibi's power, doesn't have a glowing mode and that would indicate to me he just jumps straight to the full transformation.