ADC feature explanations
Here is everything that i have gathered.

INL - Integral Non-Linearity

Basically, this is error of the reading of the ADC (and DAC) to the actual values. The value is calculated by: 

 INL = Vreal - Vmeasured


Generally the lower this value is, the better. Higher pecision bit ADC suffers from high linearity reducing their Effective Number of Bits (ENOB), consult datasheet to know more about the specific adc. More info on INL here


SNR - Signal to Noise Ratio

It is the ratio of the signal to the noise. 



The formula is signal divided by noise. From that formula we would generally want a high signal to noise ratio so that more of the signal can be seen and less of the noise. I do not know why they put this as a filter as this is an application specific measurement, different noise will hit your circuit thus the SNR will vary from application.

SFDR - Spurious Free Dynamic Range

Is the ratio of the fundamental signal to the strongest spurious signal in the output. radio receiver application, Im having trouble putting it into words but you can read more here 



From what i understood you generally want a higher ratio, but again this is an application specific measurement as it uses noise in its equation, and noise is something that is application specific.

PGA

Try as much as possible to use the least/no gain as a gain amplifier instroduces aliasing and you would not want that, the higher your gain the higher the alias too.

Simultaneous or Multiplexed Sampling

As DKNguyen said multiplexed is best case but will slightly cost you, get it if your constraints allow you.

Notched Filter

A very narrow band stop. And a band stop at 50HZ/60Hz which is also our target working frequency, really not ideal for the application i want to use it with.

AC excitation 

the system which is used for providing the necessary field current. Im not really sure how can this be used alongside an ADC. You ca read more about AC excitation here

Golds

Please refere to @Sephro Pefphany's answer