Dual hand crossbows does not work in 5e, nor does hand crossbow and shield.
In 5e? Yes it does. You cannot do this in BG3 at the moment, but it's absolutely acceptable in normal 5e rules.
*Edit: though, I'll allow that you do, technically need the crossbow expert feat to dual wield hand crossbows and actually use a bonus action to fire the second. Without that, you need extra attack to fire both in one round ^.^
*Edit 2:
While there is no "after" in Crossbow Expert, the wording does imply that you must have attacked with your 1-H weapon before you get the Bonus Action. A lenient ruling would allow you to declare that you're taking the Attack Action and your BA attack, so you could BA crossbow attack first but then you'd be required to take an Attack Action that turn.
Law of unintended consequences comes into play here. You can't just say you're "going" to fulfil the requirement after you do thing that requires it because by the time that happens you
May Not Be able To. If something says that you must do something in order to use the feature, then you must do that thing before you can use the feature.
Here are a couple of quick examples:
"I want to use the bonus action too shove with my shield, and then attack the prone character after!" - You need to take the attack action in order to access the bonus action shove here. Suppose you shove a creature first, knocking them prone... but seeing the creature fall prone is the trigger for another creature's readied action, which then goes off; this readied action may move you, or the creature, or change the situation in some other way that means you can no longer take the attack action - maybe you're incapacitated, or maybe you just have no targets to attack now and can't. Perhaps the creature saw it was getting surrounded by you and your friends, and decided "If I get knocked down, I'm not going to want to take advantage attacks from everyone there - if I get knocked down, I'll cast thunderstep and teleport away, and blast everyone around me in the process"... suddenly, when you shove them prone, you and your allies get hurt, and you have no target to attack any more. Either way, you've now benefited from the perk and not performed its prerequisite action, and can't - you've 'cheated'.
"I want to shoot my hand crossbow as bonus action first, and then stab with my dagger after" - Except, in shooting with your hand crossbow, you kill the last remaining target, and now cannot stab with your dagger as you'd planned. Once again, you've benefited from the perk without satisfying the conditional, and cannot do so.
It may seem a little pedantic, but there are situations where it genuinely matters, so, if a perk or feature says you can use it when you do something else, you *Must* do that something else before you can use the feature. This is the specified timing - compared with bonus actions (such as cunning action) which have no specified timing.
