Hi all, 
See the following documentation for the API GET /identities
https://developer.sailpoint.com/idn/api/beta/list-identities
the filters attribute supports uid eq '....' and maybe more, but it isn’t documented.
Also, it mentions name and alias, but it doesn’t say what they are. As far as I can see (please correct me if I am wrong), name is the identity attribute displayName and gets its value from the identity profile mapping and alias is the original value for the identity attribute uid and got its value from the identity profile mapping, but will not update after this (unfortunately). This is not documented either as far as I can see.
SailPoint is quite inconsistent with handling these types of attributes which is a bigger reason why we need proper documentation for this. Otherwise we will keep second guessing ourselves.
Kind regards,
Angelo