It seems that Blaise would definitely remember Lavender, but probably fell out of touch like he did with everyone. The fact she's so savvy about clothing could be a good basis for friendship, considering Blaise is all about dressing nice.
Blaise also remembers Milicent, and she has gone into the profession he wishes he had (Healing Potioneer) and Blaise would probably have seen her around the ministry! Perhaps they could work together on something at some point?
The Hounds Pint sounds like a place Blaise might go if invited by friends, but not on his own. If he met Sirius, it would certainly be interesting!
Although Blaise remembers meeting Victor Krum, but that is it. Similarly, he knows of Marcus Flint, they do not seem to have much in common at the moment. But who knows what the future brings!