1. Increasing (decreasing) native resolution - possible but not necessary.

Theoretically it is possible to install a screen with a higher resolution than the original, but in practice most of the new screens will display a distorted image or will not work at all. Even if the picture is normal, in the future graphics processor may become damaged due to the increased heat because of the higher computational load. Most often, GPU on a laptop is integrated into the motherboard, repairs to which are expensive and not always possible.
The best and most reliable option is to replace the old LCD with a new screen with the exact same resolution.


2. Upgrading CCFL to LED:

Is not possible (with very few exceptions, more on this below). These two types of screens have completely different connectors and power supplies. They are not compatible.

LCD panels are divided into two types according to the back-light:

CCFL (Cold Cathode Fluorescent Light - High Intensity Discharge Lamps)
- This type of lighting is used in older laptops and now obsolete. Usually one CCFL lamp (rarely two) required a high voltage inverter to for power.

LED (Light Emitting Diodes)
- This type of lighting has become widely used starting in the early 2010s. It consists of LEDs. Such screens do not need an inverter, and they are more energy efficient.

If your laptop was manufactured after 2011 it is virtually impossible that you have CCFL backlight.