I'm having very similar experiences! The last two frogs I bought were WAY smaller than the two I got before, and every time I look in the store, they ALL seem so super tiny. I know my babies GREW since I got them, but they were definitely bigger at purchase. It's odd. . .
I also had the same thing happen when I put Freckles into the 55g tank. He had always been my submissive sweetie, and let the bigger female push him around from day 1. But when he got into the community tank, he was a little bit snarky while he was settling in! I was happy to see that he could hold his own against the fish, and once they figured out that he WILL nip at them if they get in his face, they've been good at leaving him to his own thing. . . this is mostly with my Rams, though - as far as the Kuhli loaches are concerned, after the first evening, he has NO problems with them at all - he'll let them sit on his head, lol! So far so good in my community - hope yours goes well too!
And you KNOW froggy spam pics are ALWAYS welcome! <3 froggies!