Obito can kamui objects from his dimension & send them over to the real one without contact... However the same can't be said for bringing objects back.
Only Kakashi's eye is used for transportation of objects from the real world to the kamui dimension without contact.
Obito almost undoubtedly needs to make contact in order to do so, & there are multiple instances where he demonstrates that to us.
A)
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Why didnt he kamui all the paper surrounding konan? He needed to grab her first.
B)
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Also unnecessary, why did he need to reach for kakashi?
C)
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Now this one is interesting because obito specifically says "if I touch you, I win" meaning that he had to touch naruto, otherwise why even bother to reach? Naruto was already pinned down by the coral that yagura had placed on him.
Touching naruto in this instance was completely unnecessary, therefore he needs to do it. Its basically a confirmed fact.
Kakashi's eye (given the feats) should be capable of doing what you suggested. The main reason why double MS obito is impossible to kill.
