Because words such as 待たせられる mataserareru are considered to be difficult to pronounce, frequently in colloquial speech, the middle part of the causative passive would contract. That is, 待たせられる mataserareru (I was made to wait), would become 待たされる matasareru. Another example such as "(I) was made to buy (something)" would formally be 買わせられた ...
～くなる and ～くする are fundamentally different. For example:
to become red / to turn red
to make (something) red
to become unable to be alone
to make [someone] unable to be alone
And the original sentence is a cleft sentence where お前 has been pulled out for emphasis.
It's you who made [...
This だろう does have the function of inference, "I suppose" or "probably will ～". The subject of 侮っていた is 私, but the subject of 行動しないだろう can be either 私 or someone else who has been mentioned in the previous context. と is just a quotative particle.
I think [someone] will not act right away.
EDIT: Now that it's clearer that you're asking about the 選べ rather than the 来れば, ignore the next paragraph and skip to the end.
While え-form can indeed imply imperative, if it's ～えば then that's a provisional ("if") form, i.e. it means "If you came to my place ..." and in this context it's probably been contracted from 来ればいい, which is used ...