Good questions. I'm not 100% sure on any of this but it would be my guess that in the NHL the guys get pretty much whatever they want. Seems the manufacturers would want the exposure. Now whether or not that type of request is done thru the team or straight thru the manufacturer is another question.
I know that in the minors atleast, you might see every single player on every team wearing Sher-Wood gloves or Mission helmets. I think in that case the league has maybe signed some sort of sponsorship deal to where the players all get some identical equipment.
All equipment the players wear the NHL team purchases, it's part of the team's budget. The team also has a stick budget so the team will purchase sticks up until the budget is dry and then once all those sticks are used up (either broken or given away) the players start paying for them.
If you read the online CBA it explains the per diem amounts the players are given during training camps and road trips. The per diem is reduced when the team provides a meal or meals.