"Visual one ahead/on." Is, IMHO, unambiguos. It means "I can see the guy ahead". "Contact" means two things, "Call xxx they have your details" or "I am about to make physical contact with the propellor with the intention of hand starting the engine, I understand the magnetos are live".
I am & always will be under the impression that "Roger" means "Your message received & understood". If it wern't understood it should be "station calling xxx say again" or perhaps "G-XX say again, over". At least it was in the Mil 40 yrs ago!
And "Secure" in the Navy meant, End of working time (1600 I seem to remember).