Cash Shop Questions

Hello, I am new to the community and I am considering purchasing the $50 platinum package because it looks like with that much platinum I could afford all of the content expansions. Before I do this, I have some questions I would really appreciate if the community could answer for me.

1) Is the best gear in the game from the cash shop or is it dropped in the later dungeons?
2) Does it matter who gets the killing blow on the enemy or who opens a treasure chest, or is everything always shared equally?
3) All the armor I have tried on looks exactly the same except for color. Will this always be true?
4) Is my assumption correct that if I buy $50 worth of platinum I can buy all of the extra PvE and PvP content with plenty to spare?
5) I have seen posts about dual wielding. Is there such a thing or are they talking about using a two handed weapon?

Thank you in advance for taking the time to read and respond to my questions!

1. Dropped from later dungeons. Most of what you can buy are watered down versions of items that drop.
2. Gold from chests seem to be share and share alike. If it's one that gives out five gold pieces, say, whether you're solo or a five person party, everyone will get five gold. Item drops from monsters are purely random as to who gets a goodie and how good a goodie they get.
3. Bears, no. Most Mage and bird gear looks about the same with variations in color. Some of the bear armor has some differences.
4. For varying definitions of "plenty", yes.
5. Cinco (a dev) posted they were working on true DW, but it's going to be a while. DW currently refers to speccing a char so they can easily switch between classes. Making a bird, for example, with high enough dex that he can effectively use a bow, but enough intelligence that he could use a Mage staff.

Thank you for your thorough responses :)

The use of dual wielding is odd considering it means the same thing in every game ever except for this one.

You're welcome and please forgive my lapse in manners--welcome to the game and the forum! DW is probably used that way here since we don't have it yet and "dual-speccing" sounds weird. ;)