1) Branch versioning in UN - Maximo owns the services so it can edit to default
2) Use definition queries to break out feature services to a more granular level, e.g. Reg Station and Service Tap are in the same UN Feature Class, but each has its own service published since they use definition queries - this makes Map Manager in Maximo easy to setup and allows you to map a Reg Station to a Location and a Service Tap to an asset.  
3) Use conditional mapping in JSON mapping to transform coded values from ESRI, e.g. asset type, to text fields in Maximo where required
4) You can use a trigger field in GIS for the feature service query used by the cron task in Maximo to auto create or sync records in Maximo.  Use attribute rules in ESRI  to auto populate those trigger fields so the GIS editors don't have to do it manually.  Or you can use the last successful run time attribute added to the cron task instance to compare with date/time stamps on ESRI features to identify changes since last update.

Reference the Maximo Spatial Information Center and YouTube Channels for more details on setup.

https://www.ibm.com/docs/en/msam/7.6.1?topic=SSG2D3_7.6.1/com.ibm.spl.doc/pdf_spl_qsg.html

https://www.youtube.com/channel/UCJGFt9QBL4_HWyVdXMjLLWg

https://www.youtube.com/user/jmaior