UPDATE: I looked into a bit more and tried getting my client to crash and I finally did it. It mentioned that the reason for the crash was something along the lines of "Weak map hash.".
I'll keep this short and to the point. Issue(s):
Other than these issues, the mod pack runs extremely well and so far hasn't caused any noticeable frame rate drops despite the 100+ mods. LAN was run with 1 other person and under most instances both me and the other client were in the same Dimension at all times barring the teleporting sequence. The other client experiences no lag spikes after he/I go to the Nether. I think the random crashes are not crashes at all, rather the game closing it's self for some reason. It's not caused by any one thing and happens randomly.
Edits:
Added quotes due to editor mashing everything together.
Sorry if it's hard to read. Every time I make it formatted nicely it adds all the lines into one long one.