immutable.js for what? Seems to me you're picking up hear-say here and there but why and for what would you want to use immutable. Even redux docs speak out against it. It's just a random tool like any other, you're assuming it has some deeper significance with react, it doesn't.

> be constantly aware of small quirks like keys when looping

There are no "quirks" in looping anything. It is plain javascript. I would call "v-for" a quirk on the other hand.

    const array = []
    for (let item of items)
        array.push(<li>{item.text}</li>)
    
    render (
        <ul>
            {array}
        </ul>
    )

Recreate the snippet above, then let's discuss.