My first two questions are:

Are the grenade upgrades only for the HL2 grenade entity?

and for the Medic's abilities, is healing from ents you spawn affected by his abilities?

question 1 yes
question 2 most likely not

Ah I see. I was seeing if the health vials would scale when used. Or healing npcs/entities

The only type of healing that applies medic buff is the healing from weapons made in Horde.

I.E the medic HL2 pistol, medic mp7, medic scout rifle, medic kriss vector, spore launcher, medi grenades and the medpack weapon

Okay think you.

Which button do I press for night vision again?

Originally posted by Joebrooo:

Which button do I press for night vision again?

flashlight
your talking about the Spec ops subclass right?

When in doubt I think the class page has instructions for what keys to press for abilities.

Originally posted by Youmu Konpaku:

Originally posted by Joebrooo:

Which button do I press for night vision again?

flashlight
your talking about the Spec ops subclass right?

I havent unlocked it yet, im assuming its from the assault class? I thought every perk can equip the night vision

Only Spec Ops can. It's tied to their main perk I think.

Originally posted by Joebrooo:

Originally posted by Youmu Konpaku:

flashlight
your talking about the Spec ops subclass right?

I havent unlocked it yet, im assuming its from the assault class? I thought every perk can equip the night vision

Originally posted by saximaphone:

Only Spec Ops can. It's tied to their main perk I think.

yep. its a spec ops thing. unless you get your own night vision mod
but spec ops's night vision while on will give you headshot boosts and all that fun stuff related to your perks, and you can also see the exact hp value's of all npc's team mates. zombies. all that

Is there any way to add custom guns to the shop menu?

Yes. Press F2 in game.

Is there any way to disable boss music? I'm using nombat and the music seems to mash together and sounds awful most of the time. I have my music set to zero but it seems to be tied to sound effects. Also DK if this is the place to ask. Awesome mod still tho! Absolutely having a blast and is scary most times depending on the map.