Feature class alignment issue in Arcgis Pro.

[RobertFaison]

Several months back, I created a project to lay out burial plots in a church cemetery.  I have no formal training in GIS, and I'm self-taught.  Not knowing better at the time, I created several feature classes and didn't pay much attention to coordinates when I set them up, but nonetheless, I did create a pretty nice and extensive cemetery project, and it all looked pretty good.

This Friday, I decided to share the project as a Web Map, so other members of our church could view the maps.  In the process of uploading, I ran into issues because the coordinates used on a couple of feature classes were not the same as the Background Map, so I started making changes in the coordinates used in those feature classes.

At this point, everything blew up when viewing the project on screen, and after much difficulty, I was able to locate most of the feature classes at the prime meridian and equator and change them back, but the main feature class (burial plots) that took me days to create now does not line up with the rest of the map.  It's close but several yards off.  I have tried using every coordinate system I can locate, but I still can't get it to line up.  I would appreciate any suggestions.  Thank you in advance.

[DanPatterson]

featureclasses need a defined coordinate system, so if it was not defined, or more importantly, defined wrong, then you need to define it correctly using

Define Projection (Data Management)—ArcGIS Pro | Documentation

Once defined correctly and you want it in another coordinate system, you need to use this tool

Project (Data Management)—ArcGIS Pro | Documentation

So "define" correctly, then "project" to get it into something else. You can substitute or change the order and "defining" something that is defined incorrectly doesn't work

[LindsayRaabe_FPCWA]

Also, once you have got your coordinate system setup correctly, if you still need to move your data to sit in the correct place (due to it being created in a the "wrong" place originally based on an incorrect coordinate system) you can select all your features and move them manually. 

Move, rotate, or scale features—ArcGIS Pro | Documentation

By moving them all at the same time, hopefully they will maintain their spatial integrity in relation to each other and still fit the site they belong to. If needed, you have the Scale option (same link above) to resize everything equivalently. 

I don't know what coordinate system you settled on using, but when we're publishing to ArcGIS Online, we default to the Web Mercator Auxillary Sphere to keep it all simple and like for like (as that what AGOL uses in the webmaps).