#2
I am not really into this genre, but the riff is pretty good, but I'd simplify it a bit, or just take it apart in sections and play some of them multiple times as a main riff and use the others as bridges and coruses or whatever you like. But yeah, solid.
#3
Sounds great as far as writing and playing goes. I'm not really a fan of the guitar tone though, it sounds a bit too gainy and crackly for my tastes. But yeah, with a good drum part, this would sound pretty sick. Listened to a few of your other tracks on your page as well. I'm really liking the Original Weird Death Metal Song.

Here are two of my tracks.

Sentinel - https://www.ultimate-guitar.com/forum/showthread.php?t=1491886

Chernobyl - https://www.ultimate-guitar.com/forum/showthread.php?t=1488878