I have 3 yorkies & 2 Skye terriers, big dogs on short legs.
One of the Skyes is SO laid back that she more or less ignores the yorkies' antics, the other is more boistertous & will join in, so I have to keep an eye out.
They are both in complete awe of my old Yorkie & grovel to her constantly. When they came as puppies they were desperate for her to be mum, but she was having none of it & puts them in their place.
I just have to watch that the boisterous one doesn't hurt my smallest 4 month Yorkie puppy when things get a bit frantic, though she's never aggressive & wouldn't hurt her on purpose.
Mind you, with the speed the Yorkies shift she'd be pushed to catch them
I've no experience of Labs, but we had Old English Sheepdogs with Yorkies & they got along fine.