Its got nothing to do with Strawhat interactions. Brook, Robin, Franky, Jinbe, etc. ALL Strawhats had high panel time in their joining arcs. Meanwhile Carrot is losing to literal nobodies like Onimaru. She's not joining.
No. He has no intention of having them be part of this battle in the first place. The only reason why Perospero is coming is because there's a plot left for him with Carrot, that's obviously where Oda wants to bring closure.
No reason why Peros didn't take any of his siblings with him