Information from winbindd is treated inconsistently in it's presentation 
through wbinfo. Example - (winbind separator = + is in the smb.conf file)

# wbinfo -n Administrator
S-1-5-21-418081286-1191099226-2202501032-500 User (1)

# wbinfo -s S-1-5-21-418081286-1191099226-2202501032-500
1 CORP\Administrator

# wbinfo -n CORP\\Administrator
Could not lookup name CORP\Administrator

# wbinfo -n CORP+Administrator
S-1-5-21-418081286-1191099226-2202501032-500 User (1)

Might be nice to have wbinfo command switch to supply the "winbind separator" 
vs. extracting from smb.conf. 

Also a combined lookup command of wbinfo --user-domgroups-text=DOMAIN+USER 
which will enumerate the already-looked-up group names.