I would like to propose that we have time to explore some character development and interactions before getting into critical storyline combat; get a feel for our characters and the world a bit more. Though if the combat is integral to the character development or bringing players together, much like a tutorial at the beginning of a video game, then I am fine with that route.
In regards to the dice, I have never used them before when roleplaying. I have only ever just relied on trusting all the writers to advance an interesting story, and trying to be as realistic as possible, with the freedom of their own creativity, governed by the parameters of the game and the guidance/direction of the game master. So I am not any help in offering any particular dice system. If we go with one, I would need to learn about it from scratch.
In addition:
I would recommend maybe the game master setting up a Discord channel and providing the members access to it. That way we can discuss things OOC , propose plot ideas, ask questions, and even joint role play with one another in preparing a post, without cluttering up the message boards.