Webforms: Auto hide based on answer of other field; Alerts based on answer of field

HI, 

I have a few questions. 

Scenario: 

A team fills out a webform every time that a they take a call. There are different fields available to them to fill in. Some of these fields(especially towards the bottom) do not apply if one of the first fields they fill out are filled out with a specific answer. each of these fields in question are drop down lists. 

Question:

Is there a way that we can hide fields based on other fields answer? 

I read one discussion stating that this might not be possible, wondering what the status is or if SmartSheet is even looking into it. 

Scenario: 

A team fills out a webform every time that a they take a call. There are different fields available to them to fill in. Two of these fields are filled in by a sro (service request order) or a model #. They are manually typed in by the user. 

Question: 

If those two fields already on the sheet can we alert the user that we already have a submision for that those numbers? So that they either check the numbers or do not have to fill out form.

I was thinking of some kind of formula but not sure if its even possible. Thought i would ask first. 

Thanks yoiu guys/ladies. SmartSheet is the best and my team loves what we have been able to accomplish with it.