No. Social media links are not considered inbound links in Moz (or other link tools for that matter).

As long as all of the URLs stay the same and you aren't building a blog network (a bunch of sites that interlink), I don't think you'd see much of an SEO difference.

I haven't seen anyone complain about that particular issue which is a good sign. If/when you follow through, please comment back and let everyone know your experience!

I think this is more important for hosts and people with multiple websites (for interlinking)... Tom talks about c-blocks in ipv4 addresses which deals with seo hosting and how that changes in ipv6 (gets more vague). As usual, don't be hosted on the same server as a bunch of spam sites.

If you have just the one site, there shouldn't be anything to worry about.

It will not be considered duplicate content. However, you should use hreflang markup so that google knows that 2 versions of a page are actually the same (just translated) and show the correct language to searchers.

does the website rank well for the terms its targeting? if so, don't think google is confused.

<1% is not keyword stuffing and unlikely to trigger any flags.

you need to be more specific as to where this image is showing up in serps (google shopping, featured snippet, mobile results, knowledge graph, shopping/news/amp results, image results in serp, schema cards such as recipes).

You will want to set up multilingual hreflang tags across all pages.

This will essentially tell crawlers "each of these URLs are actually the same 'page'. You should show the correct version based on the location of the visitor" which prevents them from treating it as duplicate content.

I do believe the URLs are indexed (based on his url) and I know that you can use non-english characters in URLs.

Do you get the 500 error when you fetch as google for a url?

Add the site to Google Search Console and do "Fetch as Google" to see how they would index your pages.

Agreed, the redirects/canonicals should be permanent (well, for as long as you want the authority to pass along).

You would see changes in serps within 2 weeks usually.

I would guess similar to 301 redirects... about 2 weeks.

The faster you can get Google to recrawl the pages and index the new canonical URLs, the quicker the authority will transfer over.

You should remove it if possible. No reason to link to a dead link (poor ux, waste crawler time) or call a non-existent resource (slow site down).

However, I don't think it will make any noticeable effect on your rankings.

You'll probably experience a dip from not publishing new content but I don't believe there will be any other issues.

Updating old content (drip fed or in bulk) won't trigger any spam/manipulation flags.

Move charset="UTF-8"> immediately after the opening