Help on building an enclosure

[EddyCurrent]

In the DIY context it sounds like personal preference dictates and other than the VFD cooling fan sucking in crap if it's not enclosed I don't suppose it matters, in an industrial setting it would always be inside the enclosure with suitable filtered vents for cooling. If the wiring and layout is done properly there should not be any problem with interference.
I don't know about the Chinese VFD's but I'm used to using those with a control panel that can be mounted on the front of the enclosure set to view whichever parameters you want.

I'll give an example about the cooling fan.
At one place I worked the environment was quite dusty but not that you could see it floating about in the air. Some inverters were installed in 2m tall cabinets with vents for air intake, the vents were not filtered because the air did not seem that bad. After a month or two one of the drives failed, eventually it had to be sent back to the manufacturers for examination. It was found that the two internal cooling fans blast air over the control boards than onto the power devices, this is how it should be, but where the boards had double sided track, the connecting ferrules had been 'sand blasted' away by the dusty air being blow over them. The answer was to fit replaceable filters to the cabinets and spray a better conformal coating (they called it tropicalising, just lacquer at the end of the day) over the boards.