Bear in mind I have NEVER BEEN TO A PRIDE PARADE. I'm just making shit up.

Based on:

What they have:
Lafayette: pansexual shirt and flag
Mulligan: pansexual boxers, flag and flip-flops
Hamilton: bisexual shirt
Laurens: gay shirt and flag
Burr: bisexual shirt
Prevost: trans flag and trans colored outfit
Jefferson: bisexual suit and tie (he wore a fucking suit to a parade I know)
Madison: gay flag and rainbow shirt
Angelica: aromantic hat and a green shirt (she's just here for the food tbh)
Peggy: lesbian shirt
Eliza: bisexual shirt
Maria: as much lesbian colored shit as she can possibly wear

Yay head cannon:
Washington, Jefferson, Madison, Mulligan, Lafayette, Hamilton, Laurens and Burr hopped out of George's minivan (shut up) and gazed around at the floats and LGBTQA+ decorations.
"Holy shit", Thomas muttered.
The Schuyler's car pulled up next to them. Peggy was the first to get out, whooping, a lesbian flag printed proudly on her shirt. Eliza and Maria followed, holding hands and being cute. Angelica was the last to get out, begrudgingly taking the aromantic hat from Peggy and putting it on.

Alex had his arm slung around John's neck as they walked towards the floats, gazing at him lovingly. "John, you are so cute, we should date", he mumbled.
"Alexander, our one year anniversary is literally next week", John sighed.
"Yeah, but every time I see your cute face I wanna ask you out again."
Lafayette made gagging noises.
"Hey shut up! You're the one who's been staring at Hercules from the moment you saw him shirtless!" Alex said indignantly.

Lafayette shrugged, grinning. "He's hot, what can I say?"
"Aww babe", Hercules cooed, wrapping his arms around his boyfriend from behind.
It was Alex's turn to make gagging noises while Aaron shook his head.
"You couples are ridiculous", he said.
"Don't be jealous just because you're single", Thomas drawled, fist-bumping James. "Besides, don't you have a crush on Theodosia Prevost?"

"No!" Aaron said indignantly.
Just then, Theodosia herself walked past with a group of her friends, a transgender flag around her neck.
Aaron froze, staring at her with his mouth open.
"You're going to catch flies, Burr", James said quietly, grinning slightly.

Washington looked at them all and smiled softly to himself. He walked around to the trunk, opening it. "I got your necessary pride things", he called.
The group rushed over to him.
"Pansexual flags are Hercules and Lafayette, right?"
Hercules grabbed the flags, handing one to Lafayette before the two raced off, waving their flags and cheering.
George smiled as he saw Hercules almost fall over from running in flip-flops. Lafayette grabbed his hand and they continued running, heading to the pansexual-themed float.

"Bisexual t-shirt?" George asked, pulling the next item from the trunk.
"That's for Aaron", Alex said, stepping forward and handing the shirt to Burr, who gave him a quizzical look. "You really expect me to accept you coming to the freaking pride parade in a plain t-shirt and jeans?"
Burr sighed but put on the shirt.

"Gay flags, James and John?"
The two grabbed their flags.
"And a bisexual tie for Thomas of course", George said, handing him the neck piece. "Go on and have fun. I'll meet you back here in a couple of hours."

James and Thomas ran to find a spot to wait for the floats.
"Thomas, I can't see", James said sadly.
Without a word, Thomas picked up his tiny boyfriend and set him on his shoulders. "Which way, Captain?" he joked.
James looked around a bit and pointed to an area less crowded than the rest.
"Let's go then."

Eliza and Maria walked around a bit, looking at the different themed floats.
A girl wearing an asexual flag as a cape ended up tripping over Maria's leg as she hurried past. Another person in a genderfluid shirt came running up to her and pulled her to her feet.
"S-sorry about that", the girl said.
"It's alright", Maria responded, smiling as the girl's friend grabbed her arm and led her to the pansexual float, where Lafayette and Hercules were making out shamelessly.

"Oh my God", Eliza giggled, spotting them.
"It's so cute though!" Maria laughed.
They wandered around for a while longer until Maria stopped.
She held Eliza close to her and whispered "I love you" before pulling her in for a gentle kiss.

James was happily sat on Thomas' head, stroking his fluffy hair as he watched the floats go by. He scowled as he saw some of the men on the floats giving flirty looks at Thomas.
Taking matters into his own hands, he borrowed some cardboard and a permanent marker from a bemused lady and wrote "THIS IS MY BOYFRIEND" and an arrow pointing downwards, holding the sign in one hand and running his other through Thomas' hair.

John spotted Charles Lee wearing all black and scowling at the floats. Lee was holding a sign that read "Gays should have no rights". To John's surprise, everyone was ignoring Lee. Well goddamnit, he wasn't going to. He marched over to Lee and smacked the sign out of his hand, watching in satisfaction as it was trampled by a band in the parade.
"What do you want?" Lee growled.
"To teach you a lesson. Why the fuck are you even here, you homophobic piece of shit?" John frowned.

"My family wanted to come. I had no choice."
"Personally, and this is just my opinion, I think you're actually here because you have crushes on Seabury and George King."
Lee paled.
"I knew it! You're polyamorous!" John laughed.
"Fuck off! I'm not! The entire LGBT community should burn in Hell!"
They got into a fierce argument over gay rights which eventually ended in John slapping Lee across the face.
He heard distant cheers from a stall.
"WOO, YOU TELL 'EM BABE! THAT'S MY BOYFRIEND!l" Alex cheered.

+++

Once the parade ended, the group split into their respective cars, exhausted but happy.
Peggy was carrying so many lesbian-themed things that they took up a whole seat.
George took a look at the people in his van. Everyone but Burr, Mulligan and Hamilton was asleep.

In the very back, Lafayette was curled up asleep on Hercules' lap, the two's pan flags covering him like blankets. His 'Pride King' crown was sitting lopsidedly on Hercules' head.
In the middle row, Aaron was blushing as he gazed out the window, a lipstick mark on his cheek and a scrap of paper George assumed was a phone number clutched in his fist.
Thomas and James were sleeping, James' head on Thomas' chest, gripping the neckline of Thomas' shirt in his fist.
In the passenger seats, Alex and John's bodies were so intertwined you couldn't tell where one ended and the other began.

Alex caught George looking at him and scowled, putting a finger to his lips as he looked down at his sleeping boyfriend.
I didn't even say anything, George thought, chuckling quietly to himself.
He turned the key in the ignition and drove off.