Evolving 3* is ok, unless he got lucky with dragon daily. Evolved 3* will gain ability like increase atk/solar damage/def, still inferior to silver/gold but still better than nothing. Evolving units with 100% affection will double the aff bonus, so if you have basic/plain flower knight with 100% aff, do her first.

Besides you need good foundation to beat 80 stam dragon daily, which needs minimum 150k total damage. Doing 50 stam for 100y dragon is like torturing yourself.

Skill upgrades are not really important, you will get dupes from 11 rolls anyway.