I tried with matchmaking and to put it diplomatically it was bad. Of 5 times we made to the last encounter 3 times and all 3 we ran out of time. So yeah I definitely would recommend going with a Fire team.
You'll definitely want to use LFG, at least. I found a couple people and ran through the mission yesterday, and it was challenging but doable. It took us a couple tries, mostly just needed to clean up some deaths during the boss fight. Pro tip: don't die during a damage phase or you'll lose your buff, and that's a huge hit to your potential damage.
We didn't bother with mics or anything, so if that's something you're concerned about, don't worry about it.