Do kids pick up habits from other kids? My daughter has a regular play date with 2 boys in my condo and they are always pushing and biting, and throwing tantrums. Will my daughter pick this up, or is she more likely to behave based on how she's brought up at home?

In one word 'Yes' especially if they are young. Just like adults even kids need social validation. They want to feel accepted as part of the group. Although, the way you bring up a kid is important, they will tend to pick up habits from other kids around more easily.