So its basically Counter Strike GO?

It is kind of interesting to have some sort of game where you can establish defenses free will, but doesn't really seem all that special. It would be far better with the RTS elements more emphasized by having the 10th player construct buildings and defenses and had MOBA elements too, which allowed player 10 to summon monsters with the other 9 players acting as heroes, pushing different lanes and destroying enemy defenses.

the RTS elements more emphasized by having the 10th player construct buildings and defenses

I love this idea in abstract, but the couple of games I've played along these lines have all fallen apart whenever a less-competent player becomes the RTS commander. It seems to be tricky to balance such that the individual players can make up for a terrible general, and it's especially problematic because one so rarely plays as general that people don't learn to do so.

Hmmmm...
Apparently the topic has deviated from an FPS to a RTS.
An FPS RTS or simply a RTS can also be done.
And for the General part and balance, what can be done is that there will be no General. All the players will use voice chat or text chat in order to maintain balance and ensure more strategy.

consider (since you are early in your design) having 'rock-paper-scissors' types of game mechanisms so that you dont have as many loopholes and thus force the players to be more generalists/balanced in their strategies/tactics

consider (since you are early in your design) having 'rock-paper-scissors' types of game mechanisms so that you dont have as many loopholes and thus force the players to be more generalists/balanced in their strategies/tactics

I think a more accurate representation would be to gauge gameplay along 3 axis. A strict rock-paper-scissor system tends to make gameplay stiff, predictable, and uninteresting over time. Using axis instead allows for wider ranges of possibilities and keeps the game richer.