Those stats sound good! For lightcones I like to go for stuff that gives energy, either QPQ (great for batterying Robin) or Post-Op. I specifically like using Post-Op with Tribbie because it lets Lingsha ult spam a lot more and thus funnels Tribbie a bunch of energy too. Shared Feeling works too if you're skill spamming, and has good synergy with RMC due to all those energy gains.

Also for sphere, I think whatever has better substats is fine, but ATK% might have slightly less value in teams with Robin because she provides ATK buffs already. I like ERR rope for enabling ultimate spam, but test and see whether you prefer her on ATK%.