Noise exist while using Helix LT

[louistse]

Hi everyone, I am a new line6 helix LT user which seeking for a home studio level usage for guitar and computer audio output. 

Problem 1: create a huge voltage sound while connecting USB from helix LT and scarlett 2i2 (Gen1)   both

https://line6.com/helix/helix-lt.html

https://focusrite.com/usb-audio-interface/scarlett/scarlett-2i2

Problem 2: while playing a jack plug-in guitar, it has two sound come from the monitor(Yahama HS5): normal simulated guitar sound and a noise similar to max volume from small inch amp at the same time

https://usa.yamaha.com/products/proaudio/speakers/hs_series/index.html

So, here is my basic setting and equipment I already have.

Setting 1:

*Problem 2 exist 

 

Setting 2:

*Problem 1 and Problem 2 exist

 

of course, the setting 2 is the most suitable way for my preference, but problem 2 is the most I want to solve it cause an intrusive noise while I am playing 

Please let me know if there are any reason or solution i can duel with. Thank you so much for the help.