ok, heres what I'm trying to accomplish

forgive me for posting so many times in this forum, but I finally fiddled around with it a bit more and realized what Ive been trying to establish to no avail.

In a nutshell I’m parenting my character meshes to the armature rigs. I’m applying weight maps as the method of deformation because I have more control over those as opposed to envelopes.
I’ve made a lizard creature that I’m skinning and I’m prying its mouth open and editing the weight at the same time to keep its composure. Then I need to stick the interior of his mouth where it needs to be along with the teeth and the tongue.

But what I need to know is after I’ve edited parts of the mesh with weight properties how do I apply other objects to the rig but keep them where I put them? Because when I apply the new meshes (mouth, teeth, etc) with bone heat or add the weight heat manually it automatically deforms the newly added meshes to the already edited mesh. Is there any way to keep the new mesh where I put it instead of it deforming automatically?

I really appreciate any help. Thanks a lot.