Beyond the cube itself which I fiddled as a kid, I haven't kept up to date where the hot spots for that stuff is.
We cycle by Science World all the time, since we ....can see it from our balcony.(It looks lovely at night.) Perhaps send an email via their website to inquire in advance what they have in their gift shopp or ask for recommendations.
And I don't know Chinatown for that puzzle...just the food end of things and some sights.
Restaurants..just tons.. Are you referring to Brix? Yaletown offers much. There's an interesting genuine Mexican restaurant not far..Salsa and Algave. More restaurants with also a view of water etc.
Sounds as if you plan to pack in alot that weekend. Normally we do cycle to Granville market (approx. mid-morning) after our fitness ride on Saturdays..and do some grocery shopping. If you wish to meet.....you will be my first TE forum member I will see in person. Unless you plan to bring bikes..there is a bike rental shop down the street from us....cycling to Granville from LBS is too easy for us experts.but lovely early in morning..when not raining.