A: How can we edit links on mobile?
You should be able to just hold and click the link. If not, you might have to just delete the text and highlight to add the text. I'll be honest, our blog editor is much more optimized for desktop, but we do try to support mobile as best as possible.

How can we replace thumbnails from videos in the blog posts?
Not sure if I'm understanding correctly, but you can easily add the thumbnail image from the video into your blog post by typing the slash character ("/") anywhere in the post and selecting the Video Thumbnail option. To replace with another image just delete it and add another image.

Possible to embed tweets in blog posts or no?
No, not at this time, but this is a great suggestion. I appreciate the feedback!

I like the tool a lot.
Thanks! Glad to hear :)