Just some comments on what you have under 1, and 2.

1. The Haas controller shows four position displays (DRO):

One is the Machine display which always shows the location relative to machine zero (home).

Another shows the location relative to the G54 work coordinate setting and if this is set to zero on both axes this display is the same as the Machine display.

Yet another one is mostly used when single blocking the machine through a program and this is the Distance To Go. This is how far the machine still has to travel to complete the movement commanded in the current block. This is a very useful display when proving a program.

The fourth display is Operator and this one can be zeroed at any time and then shows how far you have moved from the point at which it was zeroed. This is essentially an incremental mode.

2, This long explanation of the limitations of the "on-machine" programming systems is why I did not even try to figure out how to use the Haas Intuitive Programming system or try to do any programming using their on screen help. All the systems intended to help a person program have limits. Once you reach these limits you have to go back and learn G code anyway if you want to go past them. It is much more efficient to learn G code right at the beginning. I do everything directly in G code either writing the program in a text editor on a PC or on the machine. I have numerous template programs for different operations that I simply change coordinates in for a particular part. The Vee shaped OD groove you describe, if you exclude a few roughing plunges to reduce the side cutting load, is three lines of program. The Haas has roughing and finishing G code routines that can be used for this type of thing and once you have written one for a particular width and depth it is a matter of editing a few coordinates for other sizes.

The Haas comes with a serial port for DNC and a floppy drive is an option. If you want to get carried away you can get a hard drive, USB and ethernet but this is a bit of overkill. I am always amused by the comments about needing CAD/CAM for serious part programming when you are dealing with a lathe. If you can describe your profile as a collection of straight lines or arcs you can program directly. It is only when you are faced with complex curves that CAM becomes essential.

As I mentioned in my other post the only question for your application is the simple brute force aspect of taking the size of cut at the feed you must use at the rpm you must use on stainless steel when using the TL1. See if Haas will provide a video of a machine doing want you need if you cannot see an actual machine.