I have 150+ Rocket souveniers and two Dino toys in my inventory, but there is no option to give them to the mini-Boomers for extra fame. Is it a bug, or am I doing something wrong?

I think you need the Dinkee the Dino Toys, the ones from Cliff Broscoe that have a weight of 0.01, not the generic Dino Toys with no weight listed.

You also can't interact with most of the children in detail unless you have a high charisma, I think.

That's a thought. Might try mentats

You need 7 charisma to interact with them.

So wear some charisma boosting clothing and take some metants. Also sadly you can only give them a toy once.

I gave one a generic dino toy (no value or weight) I had been carrying since Goodsprings. I could never get rid of it until then.

Had to look weird too. Some guy in his pajamas giving kids toys.

I use Charisma as a dump stat, so I never get any interesting messages for them.