Factors for max CP at a particular trainer level? [duplicate]

For a given trainer level; is the max CP going to be the same for all final evolutions such as Parasect and Pidgeot, or same for all 'stage 2' evolutions such as Parasect and Pidgeotto, or some clear pattern on which pokemon will have the highest CP at their max evolution?

Max CP may be dependent on the particular Pokemon line (Pidgeot) or type (Flying) or rarity (how to determine easily??) or other factors. What I want to understand is, how can I figure out which of my captures is potentially much higher CP without actually evolving and leveling them.

Solution 1:

The factors i find most important are rarity (color of the capture circle at a given CP, also Eggs), Evolution stage, and pokemon line, but the last one ties into rarity.

I have A Lapras(1267), Arcanine(1223), and Flareon(1064) all at the same %max CP (I maxed them all at the same trainer level). In terms of rarity the order seems consistent. Evolution stage most likely goes based off of max evolution Vs Current evolution. Meaning the Lapras that isn't an evolved form of another Pokemon is still strong because it's the final evolution.

Solution 2:

I'm pretty sure max CP is dependent on the evolution line the Pokemon comes from rather than the stage. Going off the hypothesis that requiring more stardust to powerup means you're closer percentage-wise to the cap, I have this example: a ~900 CP Flareon takes 1300 stardust to powerup and yet a ~800 CP Pidgeot takes 1900. This would imply that Pidgeot is closer to capping out despite being at a lower CP.