Yes, that's correct; within the Targeting step of activity setup, you can choose the "Combine Audiences" option, which will let you combine your Analytics audience & the Impressions audience into one new combined audience

For i) the typical approach involves using Adobe Tags (fka Launch) & the extension; this is effectively generating a config file, so if you don't want to use Tags for some reason, you can either programatically set config options or use your own config fileii) Yes, that extension is necessary; howev...

What is it that you want to access in the response from Target?

There are various examples of how to achieve this with JavaScript but could you explain a bit more about where/how you want to use that information? 

I'm assuming you're talking about using that 25% Scroll Metric as your Primary activity KPI; if that's the case then yes, you're correct, if you look top-level at the 25% scroll metric then it will be considering all instances of that metric. A couple of options I can think of:i) Use the A4T Panel i...

Yes you could achieve this with Impression Capping - this article explains it in detail but essentially the steps are:i) Add a custom code modification to your Experienceadobe.target.trackEvent({'mbox':'activity1234'})ii) Create a profile scriptif (mbox.name == 'activity1234') { return (user.get('12...

There is work ongoing to update the docs/process of doing this; however, currently you can include the _experience.decisioning object in the request that you make, and populate that with AT activity data including id, scope & scopeDetails. There is a code example of how you would access that informa...

You will actually need to use a custom code action because getOffers() doesn't have an equivalent action type (see list here) in the Target v2 extension. You can find a full example of how to chain getOffers > applyOffers > triggerView here.  

If a view change has potential to qualify/disqualify a customer then you would use getOffers() (with additional parameters as necessary) & then call triggerView() to then render the content from cache. More details around order of operations is listed here

Could you provide some information on what the "Experiment setup includes specific conditions" part includes?