Water resistant usually means the seals on the camera are such as to keep out moister and dust but not pressure out.
Water-Proof is similar as Water Resistant but can also stand up to certain amounts of under water pressure to keep water out.
For example..both could be taken out in the rain...but only Water Proof could go under water.

These cameras do not have a removable lens.
You can add a additional lens attachment (wide angle adapter or telephoto) and/or a filters (Circular Polarizing,UV, ect..).
The filter size is said to be 74mm.

Spectrum refers to light ...range refers to zoom capability.
A full spectrum image would come to very near infra red ...also called "VNIR" imaging. Some digital cameras can do this if the sensor is sensitive to the IR range.
The lens itself is just an amplifier..the isn't so much a full spectrum lens as it's more of a filtering out of other spectrums.

Do a Wiki search for full spectrum photograph,also one on VNIR, that might clear up a few questions and help you find what you are looking for.

Memory Stick is generally used to refer to Sony memory media...Memory Card usually refers to SD(Secure Disk), CF (Compact Flash) and SDHC (Secure Disk High Capacity)..and others.
There is a physical difference between Sony Memory Stick and other card type....other than that they are all just memory media.