Huh... just realized.
Well, it's not like its useful neways. It's not like you can change the outcome of the battle the moment you click the battle button.
Also, that's no coincidence, the flash needs those parameters to show the "battle correctly" though you might as well close the window or press back the moment you click battle because the 3 pages you need to watch before you see the reward screen was decided by then neways and is basically a waste of time.
The values for cost and total cost is needed so the flash knows how many idols it should show for a side and for pre-calculating some values, probably.
Enemy id is referring to your unique player number based on when you joined fyi.
Some stuff I copied from a battle
&kind=0&color=0 // Probably has something to do with the producer type, used for P buff effects probably
&before_attack_point=7863 // this refers to base atk points or 7863 in this case
&attack_point=8114& // Atk including buffs
&defense_point=5903& // The def points of your opponents unit, useless imo as its there for deciding if you win or lose
&total_cost=22 // Used for deciding how many idols should be shown on your side based on line up based on cost and pre-battle calculations, probably
&enemy_total_cost=34 // Same but for the opponents side
&skill_sleeve=1302002.2// Show skill with said id
&enemy_skill_sleeve=1300102.0 // Enemy skill
&reward=822 // Monetary gain
&over=0&morale_value= // dunno
&card_id_str=3301702_1101102_1302002 // Display these cards Miki+ Kohinata+ Xmas Kohinata+
& enemy_card_id_str=1300102_3301902_3201201_2001301 // Cards for opponent's side
&complete=0&friend=0&moral=0&deck_id=640919&event_id=0 // dunno
&love=3&love_id=&user_fan=22 /// Gains
&rest_cost=0&bef_cost=22&full_comp=0&slot_param=0 /// Something