Is a power sword over kill and is power armor over kill for a leader? Also is there a possiblity of a shock hammer?
No power armor at start and simple power weapons are fine as they are usually given to officers and I assume you meant thunder hammer which is a no because they are usually given to terminators.
Alright, so far we have 2 Redemptionist factions. One that's actually the Redemption, the other that's just a Chaos Cult which takes it's beliefs very seriously. Does a Power Maul count as a simple power weapon? Like if Remus' staff doubled as a power maul, would that be overkill?
Yes a power maul is fine but keep in mind the more expensive and rare equipment your leader and heros are equipped with the more likely they are going to be targeted by raider and scavenger groups because they really like your nice things and would very much like to make them their own. Edit: Dark Eldar Stranded and Mechanicus reclaimers have been added as possible factions thanks in large part to Maleth who decided take a bit of the load off of my shoulders by making the unit lists for them.
does a rocket launcher need two or one people to use? Along with its RPG variant? also are flamers rare?
All heavy weapons with the exception of a heavy stubber or heavy flamer require at least two henchmen to use but a hero of extra ordinary size and or strength can use them single handedly. For instance the team for a rocket launcher works with one guy holding and aiming it and the other guy spots and loads the launcher. The loader can have his own main weapon and can fight but he needs to be close to the operator to load the weapon for obvious reasons.
So can we have a heavy weapon from the get-go? Or would that come after a mission or two? Also you mentioned us possibly having a truck or motorcycle, how early could we get that?