I believe there is nothing wrong whatsoever in setting down a select amount of things a player can select from to make a character. So if you want to restrict Tritons to an NPC race because the pirates will be engaging them in the campaign, then you are more than justified in doing that. Likewise the same is true for multiclassing.
As far as playing a paladin with a Hexblade dip... if it was me the first thing I'd ask of the player is what exactly is their reason for wanting to do it? If it's just as simple as them wanting to be able to attack and damage using Charisma... then that says to me the player doesn't necessarily want a high Strength-- or they have a specific combination of higher abilities they want that isn't Strength and they want to save their point buy to raise up their INT or DEX or something. At that point, I'd just work it out with them to find a way to get them a higher INT bump without needing to Hexblade dip (thus still having to prioritize STR and CHA like all paladins do while also getting a tertiary or off-brand stat up to a certain level.)
But whatever the case... when someone tells me they want to level dip in a second class, it usually implies some game mechanic they want that their base class doesn't get. And rather than have them multiclass I just work with the player to do feature swaps or wholesale adoptions to bring in those mechanics the player wants. Unless of course they just want to do all the things so they can decimate everything in combat... at which time I remind them that DRAMA comes when your character's back is against the wall, so trying to OP your character with as many 'I win" buttons just ain't happening.
As far as playing a paladin with a Hexblade dip... if it was me the first thing I'd ask of the player is what exactly is their reason for wanting to do it? If it's just as simple as them wanting to be able to attack and damage using Charisma... then that says to me the player doesn't necessarily want a high Strength-- or they have a specific combination of higher abilities they want that isn't Strength and they want to save their point buy to raise up their INT or DEX or something. At that point, I'd just work it out with them to find a way to get them a higher INT bump without needing to Hexblade dip (thus still having to prioritize STR and CHA like all paladins do while also getting a tertiary or off-brand stat up to a certain level.)
But whatever the case... when someone tells me they want to level dip in a second class, it usually implies some game mechanic they want that their base class doesn't get. And rather than have them multiclass I just work with the player to do feature swaps or wholesale adoptions to bring in those mechanics the player wants. Unless of course they just want to do all the things so they can decimate everything in combat... at which time I remind them that DRAMA comes when your character's back is against the wall, so trying to OP your character with as many 'I win" buttons just ain't happening.
