Bottom 5 evolved Pokemon:
Metapod, Kakuna, Silcoon, Cascoon: 205
Spewpa: 213
source
Bottom 5 Pokemon that can't evolve further:
Wishiwashi: 175
Shedinja: 236
Smeargle: 250
Ditto: 288
Delibird and Luvdisc: 330
Bottom 5 Pokemon that fit both criteria:
Shedinja: 236
Kricketune: 384
Dustox: 385
Ledian: 390
Butterfree, Beedrill, Beautifly: 395
source