Do you think El Gusano Gigante is the giant centipede who died in the trailer?

no,

1. this has nothing to do with zilla, it is a GODZILLA reboot.

2. it is clearly reptilian, it has hands and claws and a reptilian tail, i realy don,t get why everyone says its like a centipede

3. that monster was only part of a proof of concept teaser, nothing more. it will not be in the movie anyway.

4. if they are going to base any new monsters off of old ones at all, its going to be toho monsters like destroyah, rodan,  battra, etc.

No. Different series. Then it might as well be the cloverfield monster.

Legendary wants for people to forget the other shitty movie and its shitty follow up cartoon. Its an unused monster, probably a MUTO prototype.

I am still voting for El Gusano Gigante because I want Zilla's ass to get his butt kick by Godzilla TWICE in a row during the MUTO wars.

Not even the slightest possibility. Completley ridiculous to be more correct.

My lord. Is it me or has the forums exploded with some of the craziest fan theories I've ever heard? 

LOL! The crazy theories for me are the fans that are still hoping to see other Toho monsters in this new movie, even after it's been stated ad nauseum that there won't be ANY Toho creations at all (except the big G hisself)...

MY HANDS ARE STILL DOWN FOR EL GUSANO! BRRRWAAAAOOORREERRR!