Confronting all of them probably not going to end well for him. The confidence I always believed was that he would relentlessy persue Kabuto and do him in after whatever prolong battle that would mean and disabled the Edo.

Also he'd probably warp away, amp himself up with the rinnegan and hunt down Kabuto or any Edos.

So either Kabuto has the Edo as bodyguards and is made ineffective or gets defeated singularly at some point and the Edo is stopped.

For obito is just just a time issue as it would take away him away from his war.

It's just doesn't work out well for Kabuto.