you need to get a camera,for some of these questions.
this makes no sense, the muffler should clear the fuse if its so close you need to modify the engine that is designed to fit in the plane, theres something wrong.
if a couple of buisness cards will allow it to clear the fuse, then the heat of the muffler will burn the covering on the side of the fuse they get really hot.
hobbico will send a new plane to you, in the time its taken you to post all these questions about your troubles with this airframe, some ARF planes have problems,(the little person was working too long on there shift and got tired and made some mistakes)it happens,its gotten to the point where the signs are send it back and get a new one instead of fighting this thing.
as for ARF's if they don't just click together then they need to be returned,a small mod here or there sure, but this is a bit to much,my gut tells me this isn't a trustable airframe,and take some pics so you have documentation of these issues,the last thing Hobbico wants is some bummed out customer,they want you to come back and spend more money with them there in the fun buisness,for profit of course,but if its defective then it is.