i figured it was optimus (intel/nvidia) dual gpu issues, lets see what video drivers your using
can you post out put of:
NOTE: the following directions are dependent on which drivers you currently have installed, also remember you need to either chroot in from live usb to make these changes or you can also edit the grub at boot so it drops you at a tty instead of a graphical environment, to make manjaro boot to a tty do the following:
when you get to the grub screen during boot, select your manjaro from grub, dont hit enter, instead hit " e " to edit and on the line beginning with "linux" you need to only delete the word "quiet" and replace it with the number " 3 " then hit ctrl+x or F10 to boot, and then do the following.
im guessing bumblebee installed by default, for me to be able to boot to a graphical environment an added kernel parameter makes it work. depending on what you have installed for video drivers (at this point im assuming they are most likely bumblebee)
if that is whats installed when you check
mhwd -li then do the following:
sudo nano /etc/default/grub
this is from your posted grub output (original)
now edit and make it exactly the way shown here:
GRUB_CMDLINE_LINUX_DEFAULT="acpi_osi=\"!Windows 2015\" resume=UUID=6b4e4449-c0a6-44d0-8188-f5df22ea6c83"
now save (ctrl+x, then "y" to save)
then reboot and see if its working.