You must have the best neighbours ever!
I don't know much about the Light Sussex breed, though you could perhaps just wait and see if the two youngsters are the same? Maybe with a lot of handling they'll be friendly? Just in case, as that way you wouldn't have to introduce a stranger to your flock. Someone with sufficient LS experience might correct me on that, though.
We have a very placid Ixworth cockerel, aptly named Big Boy, who will easily be held. But we also had a little pekin who attacked a toddler even though he'd never tried to dominate a (bigger) human before, whilst the other pekin boy never bothered people (but the hens - oh dear, he was a very hormonal chap!).
Maybe it's a case of finding a fully mature cockerel somewhere who is known to be friendly? I have a lovely young boy who is a cross between a Welsummer and a barn hen - I'd love to find a new home for him rather than have him going in the pot but he's only a few mons old yet. He's rusty brown with a dark green tail, I just like the look of him