>As for the limited skill I try to not bombard the player with skills at the beginning/demo of the game, or should I add 1-2 more skills per characters?
Personally I would like at least two skills per character from the beginning so there's more of a choice given the combat situation. You could also add those skills after the fight with Gorro, so you can at least get new skills before the demo final boss if you go back to the ship ASAP. You could play it off as the party learning a thing or two after fighting with her. If you want skills to only be gained by levels, then fair enough. I imagine the pace of new skills would be fine if I had decided to go to the other two objectives. I only had 3 or 4 random encounter + Gorro fight before the demo final boss, so it's not like I have the experience to say much. Regardless it's still very early on right now, I'm sure it'll be fine however you decide.
By the way, it feels a bit weird that you can skip over possible party members before leaving, I assume that's just for the demo? Unless decisions or the choice of not doing quests is a staple of the game, it seems unnecessary to let the player miss swathes of content like that. I only ended up doing that since I was in a hurry to wrap up for the day. I'll be sure to give it a fair shake next time.