Using と as 'with'

[dcent2]

I think I have it pretty much down. I have a couple questions, though.

Do I have to use 'to' right before isshou ni?

Does this work? :
じぶんと丸く収まる
(To come to peace with yourself?)

[furrykef]

Do I have to use 'to' right before isshou ni?

That's the usual usage. Grammatically there's no reason you couldn't say something like "issho ni watashi to", but it may come across as strange or emphatic. Note, by the way, that it's "issho ni", with a short "o".

Does this work? :
じぶんと丸く収まる
(To come to peace with yourself?)

Hmm... I couldn't tell you, unfortunately.

[yangmuye]

一緒に implies both subjects are agents engaged in the same event.

○太郎と次郎が結婚した, understood as 太郎が結婚した。次郎も結婚した
???太郎が次郎と結婚した, understood as 太郎が次郎と一緒に結婚した. They are gays.
○太郎は次郎と仲良しだ
???太郎は次郎と一緒に仲良しだ

Does this work? :
じぶんと丸く収まる
(To come to peace with yourself?)

I don't know what does "come to peace with yourself" mean, but 丸く収まる seems to be an unintentional verb. 自分で or 自分と won't work here, I think.

[Hektor6766]

You could say:
自分の心の中に安らぎを見いだす。

But since you are acting on yourself (or regions therein) as the indirect object, に is better than と.