Hope I can help you :) Sorry this is bound to be long but please bare with me. I actually played Kingdom Hearts II without knowing anything about chain of memories I was lost at first but I ended up understanding the story well. You've got an advantage here, you already know the story, watched the cutscenes and read the manga.
So it be unnecessary for you to play in order to understand the story, besides chain of memories can get a tad boring and even more if you already know the story. My advice is: Play what you feel like playing, you said you really want to play kingdom hearts II right? Then go for it but maybe finish Kh 1 first even tho you can fully understand kh2 without finishing kh 1.
In kingdom hearts II there is a short recap of what happened in kingdom hearts 1 but it would spoil the ending for you. I started playing Kh2 when I was just at the ending of KH1 but decided to go back and finish it since I heard what happened at the end during the recap in kh2 ,so I speak form experience. Playing Kingdom Hearts re chain of memories could end up feeling like a chore to you since the one you really want to play is khII.
You'll be just fine with the knowledge you have over chain of memories. If you want to give chain of memories a try out of curiosity then maybe you could rent it or buy it, it's not too pricey now, maybe even a friend can lend it. And yes, one of the biggest complains Chain of memories got was the card base gameplay.
I agree it's difficult and it sorta feels stiff, I rather stick to the original gameplay, tho don't get me wrong I did enjoy chain of memories. I also suggest playing Kingdom Hearts: 358/2 days (ds). The game, in chronological order has a mixed timeline.
The days plot begins before chain of memories' plot,however within the timeline of 358/2days the plot ends after chain of memories' plot had begun. That is why it's a mixed timeline because for some time(within game time) the two story plots are happening at the same time. The gameplay of 358/2 days is like the original kingdom hearts,it does have some changes but not like chain of memories.
This game will help you understand the origin of a character from Kingdom hearts II, who will have a great importance. Note: You can play Kingdom Hearts II without having to play 358/2 days first, and you would understand just fine. The games that would be somewhat confusing if you don't play days first would be the tittles after Kingdom Hearts II, since they have a certain connection to 358/2days.
I also recommend playing Kingdom hearts Birth By Sleep, you can play this one after or before kingdom HeartsII, completely up to you. It is a prequel that gives you a whole new perspective and understanding on Kh games and the gameplay is great! -------Something extra for you------ Since I see you are planning on playing the Kh games in chronological order then I do suggest, do not skip Kingdom hearts:Dream Drop Distance.
Many people do but 3D is of vital importance for the new plot line that will be further developed in Kingdom Hearts 3. If you do decide to play Kh3D then I recommend playing it after you have played Kingdom Hearts BBS or you will find yourself rather lost. The only Kh game I did skip was Coded, it has no vital importance to the plot,tho I have watched the cutscenes.
----- If necessary here's a chronological order: -Kingdom Hearts Birth by Sleep(10 years before Kingdom hearts,psp) -Kingdom Hearts(10 years after Birth by sleep,ps2) -Kingdom Hearts 358/2 Days(this is before chain of memories but the story itself ends after chain of memories has begun,so in a way is a mixed timeline, like you get to see whats been going on with these other characters while chain of memories plot had began and before it had began,DS).
Re:Chain of Memories has a very interesting but unimportant story, the gameplay doesn't have that KH feel due to lack of combos and fighting with cards only. If you want a sweet and sentimental story pick COM, but overall KH2 has faster paced action, new abilities and is much more enjoyable when in combat.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.