In the scene after the shuttle with Apollo, Pesident Roslin and Elosha lands on Cloud 9, they meet Tom Zarek on the flight deck, then proceed to leave the shuttle bay, if you watch closely you see a brief shot of one of the original shuttles used on the original series.
The weapon carried by Sue-Shaun when first meeting "Starbuck" and "Helo" is a British Army L85 Rifle 5.56mm (commonly known as the SA-80). Not a weapon generally used in film and TV making but futuristic looking enough for the show.
Opening credits say there are 47,861 human survivors.
The syringe used is a low tech prop. The "needle" is solid metal rod that is thick enough not to damage the skin and it retracts when pressed. The "liquid" is a is an inner colored sheath that is covered by a white sheath that slides over it when the plunger is pressed.