That is a great point! I am not super well versed in the tech tree, but I think coal liquefaction depends on advanced oil research which depends on blue science which ultimately depends on access to crude oil. So I think to do a full run with the mods current state you are required to have crude oil placed on the map (at least a little until you get coal liquifaction unlocked). With that said, you wouldn't need too much, and once coal liquefaction is up and you have the starter heavy oil I do agree one should be set to survive on Morphite. I do plan on adding direct recipes for Morphite to crude oil and uranium so folks could have the option to disable those in the map gen if they wanted to. These recipes are going to be a bit tricky to figure out and balance properly, but I have some ideas.
For now, you should be able (if you wanted) to go ahead and disable the vanilla ores (besides uranium!). The start I think would be quite slow, but it should be possible to progress through a game.