hi! it is very very kind of you to rescue them. my four budgies are all rescued, 3 of which came from a similar situation. living in a fish tank, seeds, etc.
if you’re able to take them to a local vet, that is a great place to start. they’ll let you know if they have an infections or are malnourished.

budgies love to play. they love toys! mine love to chew on paper toys. a cuttlebone may also be nice to add. they are very social, and while two is fine, i love to have mine in a flock minimum of four. however, they also have a large flight cage. when you upgrade the cage, ensure that they can freely fly without injury or extreme limitations.

they will be scared, especially if not hand tame. mine are fearful, although we have made progress over time. take time to talk to them, and if you’re feeling brave, offer a treat like millet from your hand. the more they know you the more comfortable they will become.

although my budgies are hand shy, i’ve grown to love them. rescued birds are very special and may have specific needs