Extending Length of Air Conditioning Drain Pipe
the first picture appears to be dish or clothes washer drain hoses. But to answer your questions: if the hoses are pliable or soft enough any short length of (PVC?) pipe similar to the inside diameter of the hose should suffice as a coupler to join two sections. Secure with hose clamps. Regarding splicing into an irrigation system; if it is not under pressure it might work correctly (or with a check valve installed). Most irrigation systems do function using water from a pressurized line although it is usually reduced by a valve.