Several questions about game mechanics


First of all sorry for the questions spam, but I've been playing for some time now and even after a lot of battles there are some points I don't understand:
  1. Completing objectives vs winning the battle: There are many battles where you have to complete some objectives to win, however if you just wipe out the rival gang you also win the battle. But, is there any advantage specially credit-wise for not doing the later? For example, with the loot crates mission it seems that if you win the battle by killing all the enemies you don't get the reputation for remaining crates (15 for crate) you only get the reputation for those crates you looted during the battle. Does this also affect the credits received when in the badlands, for example?
  2. Defending objectives: Some of the battles imply defending some loot or plasma consoles. Defending all of them is usually quite complex while just protecting one of them is much easier. It doesn't seem however to have any impact on the battle outcome how many objectives you protect. Do you get more credits (on badlands missions) or more reputation the more objectives you protect or just focusing on defending one is enough?
  3. Ballistic Skill vs Hit Chances: With weapon skill if you find someone who has very high WS your hit chances are low, so it is worth to increase that skill as much as you can. However with BS it seems like with 40-50 and some skills to avoid cover you will have almost 100% chances of hitting the enemy, so it does even make sense to spend XP once you get to that point? If it works this way, it seems like it is quite easier to level a shooty ganger than a close combat one, as not only you need more WS but you also need to increase Strength, while for shooting you just need to focus on WS and buying a good weapon.
  4. Deflected damage: With my Eschers I have one ganger focused in close combat. She has WS 70, S 40, 3 attacks and carries a chainsword. She usually kills every single enemy she faces, but there are some times when she is almost unable to make any damage, like 12 attacks all of them hitting but just being completely or partially deflected with a total of maybe 1 or 2 damage. How does this work? I'm assuming those enemies have very high armour / hit points, but the best armour I've found so far is +35 defence and when I use it, it doesn't protect near as good as they do. Am I missing something here? What can I do to defeat those enemies? Increase strength and buy a power weapon? By the way, which is the best weapon I should be using for her? Is the chainsword a good option (combined with either a autopistol or a bolt pistol)?