Two separate snapshots will exist.
Form submission is disabled in the snapshots and all scripts are removed.
It is safe to enter information in the fields, nothing could be sent to the Internet.
I do not like the redirect idea, it would not comply with the idea of archiving snapshots of old pages.
It seems that the problem is that the snapshots of your old pages are shown in Google and your pages in new place do not?
I submitted request to Google to remove the snapshots from the index, it should help your new pages to appear there.
I think archive.is better fits needs of small amateur wikis and forums than big players like Wikipedia or Stack Overflow.
Wikipedia could buy an enterprise archiving service (e.g. pagefreezer) for 50-150k$/year. It is only 0.1-0.3% of their annual expenditures.
I cannot provide higher level of uptime and support, even for money.
It is not easy, PhantomJS allows to spoof User-Agent only for the request of the main page, not for the images and AJAX requests :( So you may get something weird instead of the mobile version.
I think no. Actually the code need to be rewritten from scratch, it is very ugly :)
Fixed.
One of the servers (img.archive.is) was down, it should be ok now.