Wow! I think you win the award for finding 3 corner-cases in a single suggestion post.

I'm taking a dev note for the next release, to allow specification of credit card earning rates (1x, 2x, 3x...) as part of the configuration process. Also to allow the user to specify whether to include credit card bonuses in the main calculation, or break it out separate from the total. Both of those are do-able, and easily controlled with configuration options, so as not to "force" those features on anybody that doesn't want them.

As for creating custom profiles, I think that might be a bridge too far... We can only work with what information UA.com displays on any given page, and "detecting" the Premier level of a given passenger at search-time is probably not possible (right now).