Wilsnack et al. 1997 is interesting because it is a large, national survey (1,099 women) and distinguishs "sexual relations classified as abusive" from "consensual sexual intercourse". They mention what t women with histories of CSA women with histories of CSA were significantly more likely than women without CSA histories to report various harm (substance abuse, anxiety, depression, pain), but also consensual sexual intercourse before age 15. They do not mention harm related with consensual intercourse before age 15.
Nonetheless, this absence of evidence is already very strong evidence. The argumentation of the pedophile emancipation movement is well-known in the "child abuse industry", and to prove that volitional sexual relations have negative impact would be a very strong argument against pedophiles.
Of course, there may be a large amount of stupidity in the anti-pedophile movement, but to assume that all anti-pedophile scientists are too stupid to understand the loophole in their argumentation is nonsense. At least some of them know that it is nonsense to prove that volitional sex is wrong based on statistics about a mixture of rape and volitional sex. Moreover, they have had enough money for research about harm caused by volitional sexual relations. To assume that they have not tried to find such harm seems unreasonable.
Nonetheless, they have not been able to find any reasonable evidence against volitional relations. This is already a lot of indirect evidence that there is no such harm.