Combat System - Now or later?

Hey! I've been working a lot lately and I'm at the stage where I can already embark the player character outside the ship on the alien planet, post-crash.

However, soon after you venture outside, there'll be a situation that might be a good starting point for prototyping the combat system I've been planning for a while. Something happened to one of your crewmates after the crash and inexplicably, you will need to subdue him.

Now, the combat system I've been planning for is a turn based one which takes inspiration from Japanese RPGM games like Melty's Quest and Karryns Prison (both of them have clothes as a combat element). 

There'll be different stages in the combat system and on the actual action taking stage, you will be able to take actions that costs Stamina or actions that restore your energy levels and so on, and my attempt is to make it as visual and interactive as possible (NSFW images & animations during combat and combat actions).

Now, because it's going to be an ambitious undertaking, how do you feel about making prototyping the combat system together using polls along the way before continuing the story?

There are 2 choices:

1. Prototype the combat system now using the crewmate encounter, postponing story content until after a playable version of the combat system is done (this shouldn't really take more than a week or two to be honest, the next update wouldn't be just the Ted encounter using the combat system)

2. Make the crewmate encounter a simple dialogue that relies on 1-2 choices for deciding what happens, and keep the combat system for another opportunity. This means that instead of there being an actual combat system, it'll be a dialogue (or two) and 1-2 choices will change which scene will occur during the encounter.