4.5Kw Portable aircon

i dont think so
just dont hold it too close...

yes.

Yes it certainly would. Most airconditioning will cool below the dew point.

The dewpoint depends on several factors but mainly it is humidity.

Using temps between 20ºC and 25ºC

If your humidity is 50% dew point is roughly 11ºC lower
If your humidity is 60% dew point is roughly 8ºC lower
If your humidity is 70% dew point is roughly 6ºC lower

If it is going directly into the PC, then no. If outside air were coming in, yes.

The PC would have to be COMPLETELY sealed in order to prevent condensation. Any amount of warm air leaking in and touching cooler air/cooler components will cause the humidity in the air to condense.

Just duct the air from the thing to the intake fans of the pc case. However re. causing condensation - I have never seen an object have condensation on it while sitting in front of an air conditioning duct or window air conditioner. The air will only pick up a tiny bit of heat from the cpu heat sink and then move on to a) the rest of the inside of the pc case and b) the room that the pc is sitting in. This means that there will be no real difference in temperatures between them. Even more, the air conditioner will be removing moisture from the air, lowering it's dewpoint.