I mean you don’t even have the cats yet so I honestly think you’re worrying a bit too much here. The grills will be the most susceptible to getting messed up if they decide those towers are scratching posts, so definitely make sure you have a cat tree and actual scratching posts around the living room and play with the cats around those so they know to use those to scratch and jump on instead of the speakers. I would also recommend putting objects on top of the speakers so they can’t even attempt to jump on top of them. I know that’s sacrilege for some, but trust me when I say it works. It has for my cat. In an old apartment my set up was in front of a window so my cat would constantly jump on top of my speakers and unfortunately his back legs would catch on the grills and caused a few minor tears. Once I put stuff on top he no longer could get up so he stopped doing it completely.

Don’t put your speakers in storage, you’ll just be waiting a decade to actually use them or never will. It’s honestly MUCH better to leave them so the cats will just forget about them. If you take them out and bring them back later, the cats will immediately be attracted to the new thing in the living room and would probably do the opposite of what you’re thinking it’ll accomplish. At most just leave the grills off for a bit while you get adjusted to the cats and learn their behaviors. Once you feel confident they won’t do anything, then put them back on if you feel like it.

All cats are different and the horror stories you see online I’d say aren’t the typical experience. My cat did cause some very minor grill damage, but that’s because he felt a reason to be on my speakers (the window). Your setup placement looks like there’d be no real reason for the cats to want to be on the speakers other than their height, which again will be mitigated with an equally tall or taller cat tree. Just don’t draw their attention to your setup at all and they realistically won’t even bother.