>>58415585
No you are not forced to go into them. However every time it changes from day to night the game stops everything you are doing to show a cutscene of the day turning to night and the battle zone opening up. Its a little distracting and people have lost pokemon they were trying to catch because of the shift.

>>58415611
Stuff like growl and tail-whip are actually pretty good now, since you don't have to sacrifice a whole turn.

Be sure to buy plenty of status effect healing items. Unlike LA status effects do not go away after combat and you get them alot in this game. I find buying 5 to 10 each after each battle-zone night keeps me well stocked if not over stocked.

Great way to make alot cash is to do battle-zones at night time. Just focus on fighting as many trainers as you can. On that note you don't have to crouch to sneak up on trainers. From my experiments they don't hear you like wild pokemon.

Oh and there are plenty of pokemon outside of wild zones, some even rarer. So don't be afraid to get on a roof or go down a side ally because there could be something down there.