I don't think it's a good idea. Repairs are certain to be needed at some point and digging for one utility will mean in your case you'd have to turn off the others during a repair that might take days... and of course even worse things could happen.

I don't know about interference from electrical on phone. Maybe someone else knows. Just bury in different trenches and take pics and make a map that shows where everything is buried.

My electrical is in 4' to 5' deep and I'm told the phone will be put in much shallower. I have a well for the water.

Coontact your local building dept and see what they allow. There are standards for this but I don't remember what they are.