Would it be fair to say that the Grick's tentacles could act like grappling tentacles to make combat extra annoying for particularly large parties, requiring a DC14 Strength Check to overpower it and be able to break free?  I think I may do that when my parties encounter this creature, since I'm running LMoP with 8 players in it, and have found I need to buff up the encounters a little to make it more of a challenge.

Agreed! Good suggestion for a "natural buff" on the creature, GreyTigerFox.

The description implies that its typical strategy is to grab the nearest victim it can reach and drag it off to eat alone, so I think that's a fair decision.

make it evil

nah, its a animal, a ferocious animal, but a animal.

Would it not make sense to reverse the damages for its attacks... the tentacles becomes 1D6+2 and the Beak does the big damage of 2D6+2? 

Henxs, I would say nay as there are 4 tentacles so the 2d6+2 represents the multitude of damage from all four. 

Makes sense now that you put it that way.

Add "reach" for tentacles range

it should be DC 12 because according to the MM the base DC (if no provided) is 10 + athletics mod (+2 for grick)

I don't see no eyes yet no tremor sense of blind sense or something.

It's a mix between a quadopus (octopus divided by 2) and a worm. It is a worm with tentacles and a beak, like an octopus. Really, it's more like a squid. But Quadopus Worm sounds cooler

Ooh maybe

Why do they have dark vision, where’s there eyes?

I wasn't able to find any picures, but I found the following quote about a grick's eyes on the forgottenrealms fandom: 

A grick's head featured a pair of tiny eyes and a snapping beak surrounded by large barbed tentacles.

Here is the link:

https://forgottenrealms.fandom.com/wiki/Grick

Somehow when I encountered one of these, it had a hit range of 20ft... 

These are the best, and I want one. Who wouldn't want a Demogorgon Snek as a pet?

Quote from Beaks >>

Add "reach" for tentacles range

 it says 5 ft.

Isn't it funny when your DM gives you a Grick egg and you decide to keep it as a pet along with your Manticore (Sr. Leeroy Waffles II), and your party begrudgingly agrees to let you because you're the baby of the group? Yeah. I love my party.

G-rick