50 mm 1.8 85 mm 1.8 large dof mainly portraits.
Most f/1.8 lenses have to be stopped down 2 or more stops before they deliver their sharpest focus.
To have good subject scale in the image frame with those lenses you would need to be fairly close to the subject which would give a pretty shallow DoF even having those lenses stopped down a couple of stops .
To get a deep DoF you would have to stop down even more.
If you use a camera with an APS-C size image sensor and a lens aperture smaller than f/8 expect diffraction to start diminishing focus sharpness the smaller the lens aperture gets (f/11 to f/22). If you use a camera that has a full frame image sensor it's going to depend a lot on which camera you use.
Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks
Light direction and quality will have a lot to do with what settings will be the most flattering to the subject.
You don't say what lighting aids, if any, you will be using.
At the least I would want a couple of reflectors for fill light and a couple of diffusion panels to create some shade.
The color temperature of the light changes somewhat throughout the day too so you'll also want to keep a close eye on that.
Most of the time when I shot portraits outside I did so early in the morning or late in the afternoon to avoid the harsh and not flattering high angle light the Sun delivers as it gets higher in the sky. For morning shoots I was usually set up and ready to go just before sunrise. For afternoon shoots I usually planned to be done by sunset. The higher the sun gets the harder it is to effectively angle reflective and diffusing lighting aids.
I only rarely ever did outside shoots without lights with light modifiers on them.
I never did outside shoots without reflectors, diffusion panels and some scrims.
