No, you really don't have to cater to an attention seeker. I have a positive relationship with my stepdaughter but I still tell her "that's enough, can you go play in your room or color or something?" when she's being attention-seeking/annoying. I just say it in a polite, light-hearted way and off she goes. It's great lol 

Growing up, I don't recall my parents (or any of my friends parents for that matter) pretending to think we were interesting all the time. That's definitely a new thing. My parents would tell me to shut up or go play outside all the time lol 

My SS was a bit of a twinkle toes when he was a young boy.  He would rather dance on the baseball field and play with dandelions than pay attention.   He was a hell of a hitter though.  It was odd. He had great hand eye coordination.  I worked with him on his skills at whatever sport he was doing.  Baseball was okay but not his favorite thing.  He was a great swimmer but did not have a particularly developed competitive drive.  Football he understood extremely well and had an uncanny ability to be where he should be on nearly every play but did not have anywhere near the level of aggression he needed to stay safe on the field or to excel.  He drove his football coaches nuts because everyone of them said he had absolutely the best understanding of the game and inherent instincts but the could not rely on him to make the plays he could have fairly easily made if he was more aggressive. He did extremely well in Martial Arts and won an award from the School District for not kicking a kid;s ass when that kid attacked him.  He just paried the kids attack until the attending adults tackled the kid and hauled him off.  

Then... we sent him to Military School.  He immediately was drawn to the precision drill team and excelled at it almost immediately.  He ended up at the National Championships his first season as a core member of the team.  Both years he was on the team he was on the National Championship performance team.   He had no fear.  11Lb spinning rifles with bayonets whizzing by his head and the rest of his body at high RPMs without a flinch. He got hit a few times. carried bruises nearly the whole season and got knocked unconscious once.  He was right back at it.

The dancing fairy tendencies I would say should not be a concern.  He will grow up and those things will change.  Even if his sexual orientation does not adhere to the usual.  

My son is an amazing young man of character, professional performance and standing in his profession and the community where he lives.  He also happens to be gay.   I had inklings that may be the case when he was a preteen.  It never bothered me.  Then into his teens those characteristics faded, he  dated young women though not with any discernable energy or passion.  He came out to his mom and I when he was 22.  He is not in any way flamboyant, he is very masculine, fit and an attractive man.  He gets a lot of attention from both women and men.   But, he is unquestioningly gay.

He struggled with feeling like there was something catastrophically wrong with himself when he was in in later teens.  When he figured it out he went through a couple of years of self contempt and deep personal struggles.  He was so nervous when he came out to his mom and I that though it was over the phone from half way around the world we could hear him trembling.  His mom was completely surprised.  I was relieved.  I had suspected for years and when he was 17 he and I had a discussion that though he was adamant that there was "nothing to talk about" he did ask me to not tell his mom about the web site I found him surfing that "dad, it just popped up. I was looking at these other videos (lady porn) and I swear I must have clicked on the wrong field by accident".  I told him not to worry about it and that if he wanted to discuss anything that his mom and I were there for him.  Interestingly it was about a year later that he had what he calls his startling revelation about being gay. I actually grounded him after the porn discussion, not because of the porn but because he had violated the rules of his computer use which limited his computer use to school work.  In hind site I may have confused him with the grounding though it had absolutely nothing to do with anything but the rule violation.  One of my hindsight is always 20/20 parenting moments.

His epiphany about being gay was an entertaining story when he told his mom and I.  His high school crush/BFF joined him for Spring Break and they went all over the US gulf coast together for two weeks.   They shared a bed, showered together, were affectionate (platonically), talked about everything, etc....  He loved this young woman to death.  They are still BFF soul mates and talk all of the time.

In bed together one night on the spring break trip he was like "OMG, I'm gay!".  As he told his mom and I that story we were all three laughing so hard we were in tears.

The behavior that makes me cringe in your story is the continual attention seeking crap. His energetic flamboyance sans the "look at me" crap does not bother me a bit.

You and DH are going to have to navigate addressing the annoying behaviors while not causing potential issues with the effeminate characteristics. Which may or not be anything.

I share my son's story as an example that kids have the chance of being outstanding adults even when they may struggle as kids.   Even when parents are not perfect.

While I understand that ADHD and mental health issues are an actual thing, I do believe that they are way over Dx'd in kids and often are just excuses for crappy parenting.

Far too often the syndrome of the month is bullshit and misapplied to make shitty parents feel better about their ill behaved spawn and to provide an excuse for crappy parenting.  

IMHO of course.