Yeah, it works. But it might not work how you think.
There is a chance of the baby getting Blaze, but not from the Simisear, from the Blaziken. There isn't a 100% chance of it passing down Speed Boost; there is a chance of passing down it's other ability(ies), with Blaze being the only other ability it can get legit. As for Simisear, you can't pass down abilities from one species to a different species of offspring.