What do you mean by passenger missions? If it's transport, then the Anaconda can carry more. If it's sightseeing, then the fact that the Conda can carry more means a lot less.
See, the Saud Kruger ships are exceptional ships. The Conda is too, but in an over-the-top, smash your face in sort of way. SK ships are refined. Performance is hard to beat. I don't run a Beluga, I fly the Orca. I use the Orca because it runs so cool and is exceptionally fast. I said in another thread that if the player wants to run bulk transport from station to station, it's going to be hard to beat a Conda, because it can pack the most on board. And if you need, or want, to fight your way through along the way, the Conda again scores points.
But the OP doesn't want to fight, and I think you'd be happier, and safer, in the Beluga. I've not engineered a Beluga to G5 thrusters. Can anyone say what top speed can be attained with this ship? If you don't want to fight on these missions then you need speed, unless you evade every interdiction. The Orca with G5 Clean Thermal Spread Drives cruises 445 at four pips and boosts to 565. Mine runs at 17% heat. No weapons, no utilities aside from a wake scanner (because yeah, I need to). With a single passenger cabin for sightseeing missions it jumps 42 light years. So even if it's interdicted, it can boost away and be undetectable seemingly before the other ship has deployed his hardpoints. This is why it's so safe. Talkin' PvE here of course.
I know the Beluga runs hotter, but if it can be engineered to be faster than any NPC, like the Orca can, you'll never be in danger. The Conda on the other hand will be caught from time to time. Luckily anything fast enough to catch an engineered Conda will be blowed up pert quick. But you'd still have to fight I think, even if it's just to point at it and squeeze the trigger.
So if fighting and max jump range aren't important, I think you owe it to yourself to get the better handling, better performing, far more elegant and refined Beluga. I'd even say if you didn;t care about the SLF, and if by passenger mission you mean sightseeing, I;d say get the Orca. You'll never be shot down in a G5 drive Orca in PvE. I doubt you'll even be fired on.
So a fan yeah, unashamedly, and there will be plenty of good advice for getting a Conda. In the end it comes down to which ship feels right to you, and that usually means trying 'em both. But some ships just feel like they fit, despite crunchy numbers and forum advice.