Mik5: As long as you are involved in fixing up the Mitzvah and don’t speak/do anything else, you wouldn’t make another Bracha no matter how long it takes you to do it. I recently had to tell someone who has having a lot of trouble with his wicks not to make another Bracha even though it was almost 10 minutes because he literally spent every second of that involved in fixing up his wicks. (Asking me if he had to make another Bracha may have been a Hefsek so I preempted him by telling him “Just light, don’t make another Bracha, don’t speak at all, I’ll explain after.”
You are not allowed to blow out the candles before they have been lit long enough. Pikuach Nefesh always trumps everything. Also, since it’s an Asei D’Rabannan, you could blow them out to avoid serious financial harm, which your house burning down would constitute in a situation where there is no Pikuach Nefesh.
If they were starting a fire and you lit in a way that would lead to that then you probably weren’t Yotzei and would need to light again with new Brachos afterwards. If for some reason an Ones happened that made them start a fire, you should definitely put them out and may have to relight, so the relighting should be done without a Bracha.