Instead of the closet you can use saheeli for the same purpose.
Not really, Saheeli's ability is a -2 so you'd need to blink Saheeli to reset the counters as well.
A better combo would just be the Eternal Command combo (Eternal Witness + Cryptic Command), and just bounce + counter or bounce + tap "infinitely" (obviously broken by a kill spell or a counter so it's only a soft lock.)
Bloodwater Entity
Temporal Mastery
Conjurer's Closet
Less viable than the actual 'Taking Turns' however.
http://www.mtgsalvation.com/forums/the-game/modern/developing-competitive-modern/768745-taking-turns?page=41
Spirits
Not really, Saheeli's ability is a -2 so you'd need to blink Saheeli to reset the counters as well.
A better combo would just be the Eternal Command combo (Eternal Witness + Cryptic Command), and just bounce + counter or bounce + tap "infinitely" (obviously broken by a kill spell or a counter so it's only a soft lock.)