Try this website. It's a chart of what different cards' stats should be at 8max, 6max, 8-2, 6-2, 4max. It covers normals to ss rares.
This spreadsheet breaks down card stats for you: https://sites.google.com/site/gamingank/home/rage-of-bahamut/card-build-stats
And you can search for god cards on the wiki to see their skills: http://wiki.rageofbahamut.com/Category:Gods_cards
Edit: Apsara seems to be the hottest card right now with 17k defense on a 4-6 method and does a Big Boost to Gods Defense which is 13%
I've been playing I suppose for 5-6 weeks now. I spent $50 my first week. I pulled a Captain, Master Gunner, Master Samurai and misc rares. Haven't spent anything since. Just did a lot of farming for HP or whatever I could get my hands on and flipped it. It was very very time consuming.
I don't know what realm you are, but I had a 60+k base def deck with just rares that I 6-2'd. I think I had 2x Bucs 2x Witch and a Holy Knight.
This site was insanely helpful: https://sites.google.com/site/gamingank/home/rage-of-bahamut/card-build-stats
Last month rares were 2HP solid. Now, you can easily get every Rare for 1 HP.
You don't really need to SSR cards to be highly competitive in this game. Since you're just starting out use this link: https://sites.google.com/site/gamingank/home/rage-of-bahamut/card-build-stats
Decide if you want to focus on ATK or DEF first. Then use the link above and find the best cards for your deck under your realm. Finding Rares isn't too hard these days so definitely get 6 of each kind and do the 6-2 evo with the link posted earlier in the other thread.
Once you have a deck full of 6-2 rares then you can start focusing on getting High Rares. Doing decent in events will get you a high rare and now they have battle rankings to get high rares. Pretty much if you get any kind of High Rare you can sell it for decent HP or for the HR card you're actually after. So don't get bummed if you pull a HR you don't want.
Join an Order that is active in the Holy Wars so you get High Rares and Legendary Card claim tickets.
You'll get it. And remember the robforums are a good source of info.
this link is a great tool for figuring out deck improvements.
Personally I think two nightmares is perfect for an attack deck but that Camuila should hold you over for a while. DNP is a cool card but way costly. You might try for a trow since they've dropped in price a lot and make a great 19k atk boost for the last slot. I would suggest NM (replace Chimera), Trow (replace Luci), NM (replace Cam) as your next three attack additions. That's three boosts from NM, NM, Inu and two high atk wings. Then maybe a DNP to replace the Inu. For defense your plan is sound.
You can try at Play Store, maybe if you use a VPN you can manage to download it, or if you know a good site to transform playstore link into apk (saw one of these once, if I had it yet I could send you) or you can download from oficial website for PC, you will need to download AndApp and then the game (I can be mistaken, maybe you can play directly from browser just like Ganblue).
I was trying to take the APK Pure apk for you but didn't find it, remember to take mine there once, if I manage to find it I'll just make an update here.