Has anyone worked out how Collector is choosing the sort order for feature types?
It's not alphabetical. It's not in the order I added the features symbology?
I thought I saw in earlier posts it's going to be fixed. Soon?
Are you using a domain for your feature type/symbology? If you are using ArcMap, there is a tool to Sort Coded Value Domain that may be of help. The tool can sort by code or description.
If you are using a service on ArcGIS Online, you can use the REST API to update the types in the feature's JSON file. This thread has a brief discussion on this process.