Hi there and
to the forums!
Congratulations on Merry and Pippin, they sound like little charmers
As Therm mentioned, we'd be happy to tell you their genders if you're able to upload some pictures of their ceres taken in natural light
Here's a link that will help you do that:
Regarding the "screaming", I'm assuming you mean the "ack ack ack" sound that they make sometimes? If so, this call can be used two ways--to indicate displeasure or fear, or to indicate extreme excitement. In a way, it is quite similar to the way we use our own scream--it is positive when we scream when there is a new car sitting in the driveway, negative when you were robbed of said new car
Personally, I believe that Merry shouting while you're feeding Pip millet is his indication that he's either excited he gets millet or confused or annoyed at what's going on. It's all up to his body language. If he seems afraid, backing away and putting his feathers close to his body, it most likely is the latter option, whereas if he runs around excitedly or even puffs up his face feathers a bit, it likely means the former.
Either way, it's nothing to worry about. As long as they're showing signs of being comfortable around you, they should be just fine.
Also, be sure to check out the forum "stickies" (important threads stuck to the top of each subforum for easy reference) as well as the Budgie Articles. These contain some great information to stay updated on the very best of budgie care and practices!
If you have any questions after reading through anything, be sure to ask as we'd love to help.
Hope to see you, Merry, and Pippin around the forums!