I'll try to answer both of your questions:
Community CalendarWhile we don't have a community calendar per sé, we do keep our events listed in the following places:
- This site -> Forums -> Events. All of our past and current events are listed there in order of recency
- Discord. All active events are posted in the announcements channel on the SGN server
- Our Steam group. Our community events are scheduled there on the group's calendar
- Facebook and Twitter. We advertise all events leading up to event day
- In Star Trek Online in the in-game event calendar UI. STO specific events shows up when you open the fleet holding window
- In Star Trek Online in the message of the day. STO specific events are posted in the MOTD when they're upcoming
Ideally, we're hoping to integrate events into a calendar on this website in the future, so that there's a one stop shop to all of the community wide events that's easier to get to at a single glance. I'm open to suggestions on how we can improve our event advertising while the website component hopefully comes together, but in the interim, I hope that I'm doing a decent job getting the word out through all of the above platforms.
Discord RanksThe reason we went with officers and senior members on our Discord server, as opposed to Admirals and Fleet Captains, is that we have a presence in games other than STO, including Star Wars: The Old Republic, Guild Wars 2 and others on a more casual an informal basis. We wanted those roles to make sense to not only our STO membership, but also to our members from outside of the Star Trek franchise. Our on-going goal is to continue to expand our community beyond just Star Trek Online, so as to ensure sustainability when STO's lifespan eventually comes to an end.
Like I say, we're definitely open to considering or examining feedback and keeping our ears open to the opinions of the wider membership with that, and if there appeared to be a large consensus, we could potentially look at making some changes there. Hope this helps to address your questions and explain our thought process behind that all!