We have a few junior team members [0]. If you think you would make a great fit in one of the roles, but at a more junior level, I urge you to still apply. The respective hiring manager can let you know whether it's possible to fulfill the same role as a junior.
If you are open to people applying that don't quite meet the requirements of the position, you should change the position description. It's well documented that this type of approach tends to reduce the diversity of applicants.
(Not to be a nag - I think it is great that you folks are sharing this, and it sounds like a great place to work.)
The diversity is indeed an important issue. We thought about this and all of our job posts contain the following text: "Avoid the confidence gap; you do not have to match all the listed requirements exactly to apply.". Confidence gap links to http://www.theatlantic.com/magazine/archive/2014/05/the-conf...