OK, so I’ve roughed out some dimensioned lines to replicate a failed part. They are all straight but are just guides. How can I keep them, showing dimensions and faded a bit and untouchable by any tool? So I can use them for reference as I work out the needed curves. Love the app, similar to my old Norman Wade and table, but so many simple things are omitted or limited. 
I tried exporting a drawing with dimensions and re-importing but it added to the same layer. Oops.
This new update where all sketches are together is not the best approach.
Welcome to the Forum 
Happy S3Ding 
Sounds like you may be trying to Sketch or work on a Plane that is not the one in Focus [Selected]?
Tap the Small Navigation Cube extreme top right to make a Selection.
Tap with your Finger on the Grid to make it present a square on view.
This link covers some of the points giving you problems:
https://discourse.shapr3d.com/t/how-to-move-a-sketch-into-a-different-folder/5732
Scroll down to see suggestions on using multiple Construction Planes [CP] via Add > Construction Plane. Hiding CPs you do not need and Displaying what you need for reference may be useful.
Layers do not exist as such.
Sketches [2D Drawings] reside on the Plane where they were created. You can have 3 different Sketches, one on each of the standard Planes plus one on each of as many CPs you care to add provided that they are Offset from any other Plane.
S3D is a really fantastic tool, it does operate differently to other software but there is very little that it cannot do regarding the creation of 3D drawings. The pace of development and improvement is high and the S3D Team always on hand to help. After a short learning curve you should be ready for whatever aspect arises.
Nope.
Let’s start in Top view. I want to place guide shapes. Then make them unselectable. And prefer lighter colour. Then I want to draw using them as guides to explore design options without interacting with them.
Currently everything is on the same layer and interacts. I had hoped locking something at the very least would allow me to tell the software to ignore it. Nope.
And having the dimensions with these sketches faded as well would allow faster work.
The software really isn’t different than others. I like many things about it. Current state would never replace my Norman Wade drafting machine. Not even the earliest digitizer. However the iPad has far greater potential assuming its utilized.
I do see videos with features that are not in the Pro app and that confuses the interaction. Some looked very useful.
For reference I’m coming up on 45 years industrial design and 35+ in feature film and have tried a lot of stuff and created some of it as well. So back to playing as I try to replace my scissors handle and 3D print it.