To answer the question posed, here is the order that I would keep the list of players mentioned provided that all of them are supposed to be defensive specialists.
1. Kreidler - Mainly due to his ability to play CF if Buxton needs a day off. Unless the Twins are willing to promote Fedko while Jenkins, Roden, and the remainder of the patients in the hospital ward come back quickly as I do not know how the rehab is going for any of them.
2. Gray - As previously mentioned, he is the only player of the three who can provide a platoon option.
3. Arcia - This leaves him as the odd man out. Kreidler or Lewis could fill in for Lee. They want to give Lewis as much time at 1st or 2nd as they can. Clemens can field 1st or 2nd and we can even use Bell in a pinch at 1st.
One more idea not asked in the article. If they are thinking on a Keaschall reset, they should do it now. Let's hypothesize there is a real trade market for Clemens. Considering the number of positions Clemens can cover, they will need Keaschall to cover 2nd if he is ever traded. They should try to reset him now, before the trade deadline, so he can come back and be the regular 2nd baseman like they have done with Lewis.