Based on your description I'd say you're about half way between a completely random DF group and a good static.

The full random DF has zero chance of success based on poor communication, no time to get used to one another, no expectation of learning over a significant amount of time, etc.

The static gets all of the benefits above and after a learning period starts downing the encounter with ease.

Yours sounds like you would have a slight chance of success, but you shouldn't expect anything different than what you're already seeing. Poetic gear and future Echo increases will make t9 easier, sure, but minor difference any time soon.

Simply put: join or organize a static group, or settle for the part of the game that is made easy enough for unorganized groups.