you could place a single crown on the root canal treated tooth and veneers on the other three teeth. It is possible to use ceramics now that would allow for a good color match
Although I have not seen you for an exam, and I do not know your exact situation, I am giving you advice based only off what you have written here. Since veneers are more conservative than crowns, and if your situation allows, it would be better to have the teeth prepped for veneers. The color should be the same for all the teeth whether they are all prepped for crowns/veneers, or if some are prepped for crowns, and some are prepped for veneers.
A highly experienced cosmetic dentist along with a talented lab technician should be able to make everything match if the dentist submits photographs with your case. Your cosmetic dentist should take photos with shade guide tabs before any work is done and after any tooth preparation so that the lab technician knows everything that they are dealing with to get a proper shade match.
Douglas Jopling, DDS Dallas Texas area
Thank you for sharing your question. A good lab will be able to do a color match between crowns and veneers. I would suggest getting an all porcelain crown and the all porcelain veneers should match fine. A knowledgeable cosmetic dentist should be able to help you achieve your desired result. Be very specific about what you want. Good Luck!