I thought NOP benefitted a lot from having three ball-handlers and passers on the perimeter. That allows them more versatility in getting Zion the ball inside and made it harder to double team anyone (Zion, Ingram, Jrue) because everyone on the perimeter could make plays.
This will be even more true when they go small with Ingram at PF and Zion at C (alongside 3 guards with Redick as 3rd guard) which I don't think they have used much yet but will be an unstoppable offensive lineup that they should use more of.
So, I wouldn't give up that lineup versatility to slot in a limited 3&D wing like Harkless. That is why I don't think Beal is right for this team. They have something special there already with Lonzo, Jrue and Ingram. With Redick as alternate.
Ingram offers more lineup versatility as a highly skilled SF/PF who can handle the ball, pass, create his own shot and space the floor than Beal does.
I do like the Myles Turner as a starter next to Zion. They should offer up a bunch of draft picks and make that happen. Favors hasn't worked out as hoped. Turner can be that 3&D center next to Zion to start games and for when they need more size inside.