As someone who has learned dance by taking formal classes and choreographed their own performances, I don't think I could ever be okay in doing that.
It's something that people can take a personal stance on, but for me it's not improvement, it's laziness and in the long run it doesn't help you.
I would understand learning various dances to see what kind of common figures are used for the main structure for dance and formations, for example side stepping constantly to fill in gaps between more impressive figures or while another member has a solo to keep the others from remaining static - Just to get a feel for how the body should be moving for idol style dances, but by doing this or making a habit of it you will not be extending your own creativity. What they will end up doing is creating a glorified Love Live Medley with their name slapped on it. If they do more with Patreon, they'd be getting money for it. If they go to events and perform, they'd be getting awards for a lack of creativity and they'll be stunting their own growth in the process.
I am not saying you can't take movements which are common to the point you can't trace it back to a certain source, otherwise all movements would be completely off limits. But at the very least don't make it so painfully obvious.
If they want to be set apart from Love Live and not seen as some LLRP group they need to look at other sources and inspiration.
Some of their costumes have had very glaringly obvious links to previous LL cards in game, but let's not make it a thing that bleeds into every aspect of their group.
If they want to be original, they need to take risks, get some classes in dance instead of playing it safe and setting up people for disappointment when they finally decide to let go of the security blanket and find they can't do anything except copy LL. I would much sooner that they just suck but remain original than be adequate (if that) by stealing.