A few months ago I would have said that we were just following behind the JP version, but with the recent events being way out of order, we have no idea when things are coming. From the looks of things, we are still following JP content wise, just not timeline wise. That's to say that we have a lot more similarities to the JP version of the game than the KR version.
Unfortunately, it's hard to help you without knowing what childs you have. Generally, I use my PVP team for hard story mode stages, at least for the first time. My team consists of:
I use two attackers because 5 stages sometimes needs more DPS. If surviving is the issue, replace Syrinx for Maat or high uncap Leda.
Don't worry. Prior to ranking calculations, the DC team looks through rankings and bans all hackers. Only after they are banned, do they calculate the rankings for rewards.
They did this multiple times during both Ragna's and will probably be doing it periodically throughout WB.
I like the idea of changing up Rumble. From playing other similar games, alternative ideas could be:
Buffing certain elements
Blacklisting certain characters
Static effects (all characters deal poison, bleed immunity, etc.)
There are a ton of different things that can be done to Rumble to make it more interesting and less stale. Since global is looking for ways to distinguish itself from KR and JP, I think incorporating dynamic changes would make Rumble much more fun.
From the developer's perspective, it would mean people being forced to use a variety of Childs, meaning more pulls and more IRL money used. Seems like a win-win to me.
TLDR; Add Weekly Rumble Changes-> Profit.
Also, this Comprehensive World Boss Guide is still mostly relevant, just ignore the WB-specific sections:
Looks like this was answered about 6 posts down; she's available in other versions of the game: