FJC 6014 Vacuum Pump Adapter, yellow

Will this let me connect my automotive R134a manifold to my household R134a/R22 vacuum pump?

I have a r12 vacuum pump. will this convert it to be used with an r134 hose to evacuate the system through r134 guage set?

I have a refrigerant recovery tank with high and low fittings will this make the low side(blue) connect the yellow port on my gauges?

Will this connect an r12 hose to an r134a can without leaking? Is there an o-ring?