First of all, don't visit these profiles or interact with them beyond choosing of your own volition to report what you feel should be reported. I'm not directly linking any of these either and I have reported every account shown.
I've removed the identifiable information from this profile because it's an abused minor soliciting sexual contact from adults. Paraphilias cluster and so do paraphiles, meaning you can find pedophiles and their victims easily through zoophiles on Twitter. For some reason, zoophiles have had an active micro-community for years on Twitter. If you check the above minor's 5 followers, you'll see the pedozoo following them that led me to this account (it took less than five minutes of looking at zoophiles and who they follow to uncover this particular example), as well as another trend in their followers:
ISSYSISSY97, Mars_K9_, and slutlover490 are all either transgender themselves or trans fetishists (what's the difference anyways?). The others are more strictly pedophiles (although prince_jer75495 shows interaction with zoophile content, circling back to the zoophile connection). The curious thing is the bigwhitecaulkk account. Here's the entirety of their public activity:
Hundreds of followers, yet only four reply tweets. This person is very obviously operating in DMs, so why would so many people follow them? Some of these accounts will use the "circle" feature on Twitter to only show their content to other confirmed pedophiles, but there's another reason: The predators and the victims can use these follower lists to discover each other.
This is the VERY top of his followers list when I open it. The accounts with redacted names are openly broadcasting that they're hypersexual teenagers (all have been reported to Twitter). Then there's these one (pfp on the second photo had a selfie of an apparent minor, so it was removed):
"No limits" means they trade/distribute child pornography. It does NOT that they don't judge other people for their kinks. If you hear anyone telling you this obvious pedophile lie, then do not trust them on these matters. The added implications of "preferably someone irl" means they're looking to abuse minors in person, if that wasn't clear enough.
To circle back to the original minor's profile, the ways these minors broadcast their age to avoid deletion by Twitter is one of a few methods. The very first image shows that some use basic math. Instead of 15, they'll put "20 - 5" to seem like a 20 year old born in May then confirm their minor status elsewhere, and it might not get suspended by Twitter immediately. Another method they use is Roman numerals (putting examples of both the basic math and Roman numerals approach):
Lastly, some will put the year they were born instead. Such as a 15 year old putting 2k9 in their location, and then "age in location" in their proper bio. There's other variations, like putting an exclamation point instead of a 1 in the tens column, or putting a slash between the digits. Beyond interacting with NSFW content, they'll put these indicators into their posts to make their intentions clear:
And, of course, sometimes they make it as plain as day:
I don't necessarily know what all these emojis convey. The football clearly holds some significance to these groups (male?), but the devil emoji seems to imply they're a predator actively seeking victims. Many of them have Discord/Telegram in their profiles and use Twitter to funnel more victims into private servers/TG chats.