edit to add: you can still get items from sparring. haven't yet gotten the Harness, but I did get the bandit's dagger from Barrel. still checking for Harness.
second edit: it says I already gave Caleb the Harness Collar and Leash, and I got the Harness a second time. I didn't get it again so i think all you gotta do is beat Barrel and it's got a chance to drop. specifically seduce win, checking if you have to be a top or bottom in specific but the way I got it was spamming the "fuck his face" choice after seduce winning.
last edit: yeah just seduce win. if you don't have one, it should eventually show up as a choice after winning.
additional solution for the first one if your good with using cheats, you can use the cheat menu and just grab a second one. I'm gonna go beat the shit out Barrel now to see if I can get another one without cheating. I'm also gonna check if seduction changes it and I can get it from that if beating his ass doesn't.
GL on Lizard's, I am still uncertain of any ways to trigger it and not the other without reloading. hope you can find a solution! or mine works. either way, hope you succeed.
also, np and thank you! I try and reply a lot because I really like this game and want other's to be able to love it as much as I do. sometimes I miss stuff cause I'm forgetful or something bugged, but if I can help i always like to try lol