The fiber glass won't off gas... I think it's more about directing airflow than insulating for warmth... sound on the other hand may factor in. Use an adhesive that doesn't melt your foam if you use foam as a replacement otherwise I'd think something that's stable (doesn't soften up and loose it's adhesion) when heated would be my main concern. Most any auto adhesive should work.

Give me ambiguity
or give me something else