Item 1 is a known issue and will be addressed in VX.2.3.
I don't see the NAME_PLACEHOLDER property as you describe, maybe you mean the location of 'name', in general placeholders show the location of properties where you have added the to a symbol but with no value enetered, the value being populated by back-annotation or packaging for example. Placeholders can be switched off in settings, though they are useful during creation of symbols.
Annotation of names to link symbols is controlled via Settings - Advanced - Automatically synchronize Links and netnames - hence the bus name appearing.
The last item (4) is also a bug and will be logged by Mentor.
For item 3:
In VX.2.1 we removed the need for the 'bounding box' the area surrounding the symbol that was used to calculate net avoidance. In VX.2.2 we introduced a new symbol type of Border to avoid issues of selection. To update your border symbols simply open them in the symbol editor and change or check that Symbol Type is set to Border. For objects such as notes or tables if you have them, check that they remain as Annotate type. This should then avoid the issues you are seeing.
Netlist flow with symbol libraries or integrated flow with Central Library? In either case I am seeing this property as Pin Order. There is something in your settings creating this, possibly a user defined property called NAME_PLACEHOLDER. It isn't a property delivered with the tools as far as I can see. Check your Property Definition file(s) and map.cfg or mapnl.cfg to see if any contain this property.
It is an integrated flow with Central Library.
I checked the definitions in the "Property Definition Editor" --> There is no "NAME_PLACEHOLDER"-property specified.
I checked the definitions in the "map.cfg" file --> There is no "NAME_PLACEHOLDER"-property specified.
I checked the definitions in the "mapnl.cfg" file --> There is no "NAME_PLACEHOLDER"-property specified.
But it seems that following has helped:
1. Create a property "NAME_PLACEHOLDER" in the "Property Definition Editor"
2. Open the problematic link- and hierarchical-symbols in the Symbol-Editor
3. Save all open symbols in the Symbol-Editor
4. Run an Symbol Update in the problematic schematic
5. Delete the property "NAME_PLACEHOLDER" in the "Property Definition Editor"
6. Open the problematic link- and hierarchical-symbols in the Symbol-Editor
7. Save all open symbols in the Symbol-Editor
8. Run also an Symbol Update in the problematic schematic
9. Delete the problematic symbols in the schematic and place them again.
It sounds strange, but seems to be the solution so far.