About the financial part, I am not so keen about that because it took some time for the interface to work . In the past there was a monthly download of the transactions, wich then were reconciliated by the account club.

About the equipment classes you are on the right track.

We defined:
Pumps --> centrifugal --> ksb, dresser, etc..
rotary --> viking, leistritz, moyno

All of course properly coded.

The nice thing about it that you can build asset (equipment) parent-child relationships

Lets say
Production Area --> Powerhouse --> Boiler X
Boiler Y
Generator Y

All the control valves, transmitters, sensors, fuel pump etc. make them child object for Boiler X. And the costs are rolled up to the boiler.

For a typical machine train like a pump, I would make the pump the parent asset and put the driver and gearbox like a child object.
I would divide the equipment in logical functional blocks and avoid coding on component level like bearings, rotors etc...

If on a certain vehicle I have two engines, like a self propelled crane, I would make the vehicle the parent, and attach the two engines like child objects, since you would service/repair the engines according a predetermined method.