You've got more than enough you want to do to warrant having local service providers come out and have a look in person. And if you aren't going to build it all yourself you need to do that anyway.

I was trying to find an app or company that can add designs to existing. I've done that for in the home.  Was hoping to find something for outside as well

" I was trying to find an app or company that can add designs to existing. "

Forget about the app....that won't provide you with anything useful. And neither will any online design services. For the type of landscape design assistance you require, you need onsite help from a local landscape professional. Better retail nurseries and garden centers often have lists of designers they refer to if they don't have any on staff (some do; some don't).