I would let them freely choose whichever has a concept or personality that appeals to them to try. Just be ready to reduce the difficulty of the encounters ( maybe reduce an enemy or two here and there)
The point a to have fun, not grind through game mechanics to get from start to finish. So they are more likely to have fun if it's a character personality that they want to/excited to play.
That said, if, and only if, they are staring at you overwhelmed for guidance, I'd probably go with the cleric cause he heals and has a good connection to the starting plot hook and good ac, the noble fighter since he has the potential to be one of the most proactive personality type ( compared to the cleric that is very passive waiting for others to lead) and he has good durability, and for the third I'd probably say wizard for his potential to hit multiple targets depending on spell choice.
I did also really like the rogue for having a distinct personality but the smaller the party the less likely he'll be able to get his sneak attack bonus. Likewise the folk hero fighter is primarily best at ranged attacks but with a smaller party he has fewer meat shields to distract attention. That's my take anyway.
But again, I'd only suggest those 3 if and only if they are totally lost in terms of picking themselves. For instance maybe none if the players wants to learn about spell casting, in such instance the two fighters and rogue are your best mix, etc.