I'm a bit torn as to which Shield member to split off into a singles match between Ambrose and Reigns. Ambrose because he's the most well rounded and Reigns because he could match up better due to his size.
However I think it's likely going to be:
Ambrose/Reigns & Rollins vs Team Hell No
The other person not in tag match vs Sheamus/Ryback
One needs to win the Tag Titles off Team Hell No and while I could realistically see Reigns going over Sheamus, unfortunately I could also see Ryback/Sheamus going over Ambrose.
The Undertaker will make sure to take a few seconds longer.
Ambrose should be the one who should do the singles matches. Reigns is far too green. not saying hes awful but Dean has the experience on his side of carrying matches with the best in the business.
HOW TO MAKE A DEAN AMBROSE
Not removing until:
Aries vs. Styles [x]
RVD loses the X Division title [x]
Cena/Rock loses WWE title [x]
CM Punk regains WWE title 
Dean Ambrose wins any title [x]