Yes, it was not really a secret that Clark was an orphan, but it wasn't really something he brought up a lot. Maggin noted in the MIRACLE MONDAY novel that those who did know tended to quickly forget since Clark took after Jonathan Kent so much. Luthor was hurt to realize that his own, biological parents loved him less than Clark's adoptive parents loved Clark.
"Visiting relatives" was not a problem, since Jonathan Kent did have many living relatives who turned up in Superboy stories, most notably his wealthy brother, Kendall Kent.
Clark celebrated the day the rocket landed on Earth as his birthday, or "Earthday":
http://www.geocities.com/the_time_trust_2000/calendar.htmOne thing that seemed strange to me was that Clark Kent and Linda Danvers sometimes introduced themselves as cousins too. Anyone who wanted to do the least little bit of research could have quickly found out that both were adopted... that the Kent and Danvers families were not related... that Clark was often accused of being Superman, and Linda was often accused of being his COUSIN, Supergirl... hmm, seems like they got a bit sloppy protecting the secret identities there. But I like the idea of Clark and Linda being cousins, so I just try to overlook that.
The birthday topic was discussed here:
https://www.supermanthroughtheages.com/phpBB2/viewtopic.php?t=729&postdays=0&postorder=asc&start=0By the way, in one of the very last pre-Byrne issues of ACTION COMICS, Superman is briefly tricked into thinking that the spirits of Jor-El and Lara somehow survived the destruction of Krypton, and he uses the Fortress technology to create cloned bodies for them. They decide to use secret identities of their own on Earth while Superman trains them to use their powers properly, and Clark then visits the Daily Planet with them in their Earth guises, introducing the couple as Clark's recently-rediscovered biological parents! The whole thing of course turns out to be a cruel hoax on Superman, but since the Earth-One continuity was wiped out after this story, we never learned how Clark explained the situation to his friends afterwards.