1:32 the birds used here are very different in prototype. 2:51 king pig is looking in a different direction. 8:01 he is also a different shade of purple.
I think Drill at least took inspirations from Hal in design. Although I am aware that this could be a new bird since it probably wouldn't boomerang like Hal does. Then again Chuck's ability is a bit different in Space compared to the original Angry Birds. Plus in space there is no air and boomerangs wouldn't work properly, so even if Hal was indeed planned for Space, he would have a different ability anyway.
I’ve got a couple theories 7:48 this is probably an ice bird beta design and this makes a lot of sense with a blue bomb text in the files 7:54 I think this wasn’t gonna be hal like I originally did but I think it took some inspiration from hal with the design 8:04 this is very far fetched but possibly when laser bird got damaged enough his goggles would come off or you could remove them just like if they were a cosmetic or something 8:23 idk about this one 8:46 these were probably used for when they were showing the player how to use a bird but chose the other text instead before out right removing them from the entire game 9:23 could be used for cutscenes but I honestly don’t know 11:25 I have a feeling they removed that one because it was too realistic 11:40 maybe something to do with angry birds Star Wars but probably not