[RPG] If a PC contracts lycanthropy (werewolf), do they gain the abilities in its stat block

No. They need to Hit.

I think you're reading too much into wounding. There's no reason I can think of, in terms of defined game terms, to think that wounding refers to damaging vs. hitting. In other words, the rules don't tell us to prefer one over the other. In general.

However, flip back a few pages: "Player Characters as Lycanthropes" says, in part

A humanoid hit by an attack that carries the curse of lycanthropy must succeed [on a save]... or be cursed. (MM. p.207, emphasis mine.)

There it is, as you first described: the save against cursing is part of the "Hit" clause and comes into play whenever a bite hits, even if it hits for no damage.

Some have expressed concern about what hit points represent, and whether a zero-damage hit is an injury or not. That way lies madness, I think, and we don't need to go there as Hit is a defined term.

The infobox makes it seem that loss of character control only happens if the PC embraces the curse and the DM chooses to take control of the character, and therefore simply not embracing the curse would suffice to keep the character as a lycanthrope complete with powerful boons like damage immunities but without any drawbacks. However, the lore earlier in the lycanthrope chapter suggests that the condition is impossible to resist during full moon:

A lycanthrope can either resist its curse or embrace it. By resisting the curse, a lycanthrope retains its normal alignment and personality while in humanoid form. It lives its life as it always has, burying deep the bestial urges raging inside it. However, when the full moon rises, the curse becomes too strong to resist, transforming the individual into its beast form --- or into a horrible hybrid form that combines animal and humanoid traits.

(from Monster Manual, page 206, under Curse of Lycanthropy)

Even a character that resists the curse is unable to control their bloodlust during full moon, as is traditional to werewolves in fiction. Ask your DM to keep track of the phase of the moon while you're infected so you know how fast you need to get a remedy or other countermeasures.