Did you check the fitting selection in the little plastic bags hanging on the hooks? Will be around the other fittings but not with either PVC or the barbed. Its where the brass fittings are.
You will inly find those online. They should have the 1/2" to 1/8". You may need a coupler for that one. The 1" you can do with a 1/2 barb and a 1" to 1/2 reducing coupler. The T fitting, you can get a slip x slip x female thread and get a threaded barb