If you've got a non-beveled screwdriver bit for e.g. a 3/8 drive (that's how mine works anyway) you can try cutting across the top of the bolt head and making it into a combo torx/standard. If there were more room, I would suggest using an impact driver (not air impact, the hammer kind) and an external extractor, but I don't think there's enough clearance to get it over the head there.
Heat probably just won't do you any good, because the fluid will carry away the heat anyway.
If you manage to get them out, make sure to get hex head replacements so you don't have this problem again. I found some on eBay with a zinc coating and flared heads.
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