Holdsworth did reject a new deal. The general consensus is that Clark told him he wasn't going to be first choice anymore, and he left because he wanted first team football, which is fair enough. It's also rumoured that he was offered less than he was currently on. He's a decent enough player and will do alright for you, on the whole for us he was a steady player who didn't stand out positively or negatively, which is possibly what you want from a full back.
It will be interesting to see how you do given how many of our former players you've signed. I can't see Parker doing anything, but the other three may all prove to be decent signings for you. Worthy can't pass or shoot to save his life, but always gives 100% and can put in a tackle, I really liked him when he first broke into the side but over the past couple of seasons he's been woefully inadequate and we were right to get rid. Maybe if you play him alongside an older head he could prove to be an asset. Holdsworth will be a steady League One right back, he also won our POTS playing in midfield, he's better in midfield but him and Worthy will be useless as a combination, so I imagine you've signed him as a replacement for Eardley. Finally, Pav is infuriatingly lazy and bone idle, but he does have a knack of scoring goals, just make sure Penney doesn't upset him, as he's the definition of a confidence player.