I Installed LineageOS 14.1on my MI4c and found more battery life, less heating and more speed. AH, the most important, finally without bloatload Apps and with all google Apps and Assistant that work as they should.
Still in love with my white Mi4c too! Still working like a charm. Only had to do two things up until now to have him working as new: a battery change and a cleaning of the GPS antenna contacts because the GPS stopped finding satellites.
As to the change to the lineage ROM never thought of it very seriously. Maybe some day. Does the edge controls work with that ROM? After almost three years of using them as back button right now I can't live without them