I expect Baird brews all of the Wolfsbane for Nathan, Charlie and Grace so Baird is probably over Nath's house quite a bit dropping of the potions and the like.
For Liv I reckon Baird teases her a little bit and gets impatient when she's being shy or difficult. He also won't understand her aversion to guys either and will find that quite frustrating, too. He'll still love her though - he'll just think she's weird.
Tris will interest Baird! He'll want to know why Baldric likes her and between being an arse he'll watch out for her and be a good friend. Sort of like a, I'm the big brother and only I can tease my sister scenario. He'll beat up any mean Slytherins that try to hurt her.
For Addie, perhaps they study together in the library? They can work on their Patronuses together and do some other bits to ensure that they're super-duper.
Keiran will be public enemy number one in Baird's books if he ever raises his voice to Baird. To the point where Baird will make the House Elves spit in Keiran's food in return for Butterbeer.