Originally Posted by
Malisteen
Below level seven, conquest pally is basically 'just' a paladin. Slightly weaker channel divinities than most, though still decent, oath spells on the betyer end, but mostly you're the same heavy armor wearing, smiting, healing melee weapon guy as most paladins. The only real difference is that you might raise cha with ASIs before whatever your attack stat is. But paladin is one of the better base class chassis, so there is no reason to be unhappy with that.
The issue with conquest pally in curse of strahd is that a lot of the tougher enemies that syart showing up right around the time you're coming into your own with aura of conquest are immune to fear. Enough aren't that you'll still get use out of it, but it can be a bit frustrating.
As for the other questions, there really isn't a right answer to them. Conquest pally gets big boosts at every level, so you can absolutely go straight paladin. That said, hexblade has a monumentally overstacked first level, so the one level dip is worth it as early as level 2. Level 1 even, if you prefer medium armor for aesthetic reasons. And the hexblade's curse in particular gives you something to do in fights against lone, tough, fearless guys layer on.
A distinct down side that you might not recognize at first is that you really want, bordering on need, warcaster if you dip hexblade, where as a straight pally can ignore it and actually max out their cha mod by level 10 instead. Then again, warcaster also gets you opp attack booming blade, which is a great tanking ability against those fearless guy.
On the OTHER other side, athletics is a really good skill for conquest paladin. I regularly find myself trading attacks for shoves. A cha primary multiclass will likely lack in that regard, though not TOO too much, since you still need 13 str to multiclass, and the single classed conquedin doesn't raise attack stat in heroic tier.
So yeah, its really up to personal preference here. Single classed strength primary gets conquest stuff a level earlier and is generally a bit better at the fear and aura stuff, at least in the levels you'll be playing at, due to not spending an early asi on warcaster and having a better athletics skill. Non-dip can also change weapons up on the fly for some reach. A back pocket whip in particular is nice. Hex dip, on the other hand, while being locked into a single melee weapin, is more generally versatile, having a decent ranged attack, slightly better all round damage after they're able to boost cha, much better damage in boss fights with hexblade's curse, and is less fear dependant for control with opp attack booming blade.
In CoS I'd kind of lean in favor of the dip, for the extra tools against fearless opponents, but it really is an open choice.
As for assimar or human... close call either way. A vuman dip can go 13,14,14,8,8,16, and take warlock at level one with warcaster, wear medium armor, and still max cha by level 10. A human no-dip can go 16,8,16,8,8,16, with heavy armor master, which is amazing in a 1-10 game, and also max cha, though they'll still be hitting with a 16 str at level 10. Can even sack con down to 14 to play without a mental stat penalty, which I know can be a roleplaying hang up. Hard to say which I'd prefer between the two.
Fallen Assimar can do 16,8,14,8,10,17, with or without dip, which is amazing if your gm allows the UA menacing feat. The skill feats seem to be abandoned content, though, so I wouldn't count on it. Barring that, the only half feat for cha available to you is actor, which gets a big giant shrug from me, so you might as well drop cha doen to 16 to get either 10 dex or int or 12 wis. The racial features are still great in themselves, mind. Once again, it comes down to an aesthetic choice.
That said, IF you decide to dip, consider the half elf. Can go 16,8,16,8,8,17, dip at level 2 or 13,14,14,8,8,17 dip at level 1 wearing medium armor, either way nabbing elven accuracy at level 5, letting you still max out your cha by level 10, and giving you trivantage (with prone being your primary source of advantage), potentially with 19-20 crits from hexblade's curse to smite with.