Can't they plastic weld something for the reflectors? I've had bumpers molded and stuff shaved in the past and I never had an issue with cracking. My wife's old Integra had fully molded side skirts, rear bumper, and 3 piece wing and none of it ever cracked even though it was a daily. My old Maxima had shaved antenna, keyholes, and some other stuff and it never cracked. If they use stuff with similar expansion rates, it shouldn't crack. I even had an Audi TT fuel door molded in and functional. As long as there isn't too much body filler, it should be ok.
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