KevinRoach:
You mentioned that the Wemos board wouldn't be pwerfull enough for the project
No, I said it might not be powerful enough. You will have not told us what information you want to see on your phone. Plain text or graphics? Current values or historical? You asked if it can be done without using a cloud server. If you expect to be able to do all the stuff you can do with a cloud server, then esp will not be powerful enough. If you keep it simple, it will be powerful enough.