"Due to some spammy links"
- I'd suggest checking those out first (remove for example). Please know that the spam ranking score of MOZ is'nt from Google, google might look different towards the use of spammy links.
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"Due to some spammy links"
The quality of responses on this forum is kind of dissapointing. Anyway: the following 3 things apply here for any new and existing domain:
1: a good structured website
2: quality content
3: quality backlinks
If you manage these in a good way then the rest really will follow. Buying links or links with the intention to pass ranks is forbidden by google, and pretty much punishes your website for doing that.
Wait for a while. Or place a backlink here and there in order to get the crawler on top of it a bit faster. It's not Google.
Create content thats relevant for the users outside of canada.
If it's one day, i woud'nt worry about it. If the problem is still there after a week, let us know.
Your blocking a crawler to access your page. Clear it.
De-indexed would mean it is removed from google search completely. Your having a 'temporarily' being shown and not shown into search. This usually is the result of a bad backlink profile happening, so i'd suggest to check the most recent placed links, and adjust accordingly.
It's another thread in where he asks for the same thing; alter photo's without leaving a source or copyright credit. I really woud'nt do that if i was you. There's severe penalty's if you do that and the owner might decide to bring you up to court. You might get away with 1 to 5 photo's but if they have you on their list and your having up to 30 photo's a year later you might be getting into serious stuff.
Ive posted this before, but, the use of H1/H2/H3 compared to only use of H1 or H2 dont matter really that much. We had a very well running website, 1500 clicks a day or so, we had a argument on the use of only H2 and if we switched that to H1/H2/H3 / correct paragraphs if it would change any. So we did, and 6 months later, not really a change.
I kind of have the feeling that description and the way you publish your content in relation of H1/H2/H3 tags are kind of ignored by google these days, as google pretty much decides now on how to display your relevancy in search. So just make sure the content is OK, and your good really. Dont hurt tho to have things put up correctly.
You could use Cloudflare, free version. It's a CDN which offers a nearby server location in the USA.
You answerred most of your own questions i think.
1: Yes. If you have genuine unique content google and partners are more then happy to take you aboard.
2: No, not really. DA is measured on behalf of the incoming follow links. If the content would be better so should your general site appearance become in search after the migration.
3: It's half work but it's a start. If you see a positive gain after the change then it's wise to change the other pages as much as possible as well.
A good oppertunity to start with it now. 
If you put up a 301 redirect, then in theory all the 'linkjuice' should follow the new domain. However if you do this now, and like for example give out the domainname in a few weeks, that linkjuice would be no longer passed because the 301 is removed. So in best theory, is to setup a 301 now, and start changing those links that originally point to that domain, and change them to the new domain.
It's intensive, but you should have done a bit more research when launching a new domain.
Correct, it's listed on https://webmasters.googleblog.com/2009/11/hard-facts-about-comment-spam.html for example (google's own blog). You really need to avoid doing that practice, and second, most of the blogs now only offer a "Nofollow" based website link (that is if they ever show a website adres within the template).
If you want to get links, a good start is to signup your website to category's / business listings that are relevant to your website or service you are providing. It might take a month or so to be found, caught up and see some changes going on. Buying links is a no go really, as that is to bypass a natural linkbuilding.
It's more of a user-friendly snippet then it does anything to your (local) SEO.
"i know there could be copyright issue. what can be done to avoid this issue. "
I dont think you should be getting any advice for this at all, since copyright exists for a reason. I'm not going to tell you on how to avoid being caught using copyrighted photo's.
There's a flag button on the right of each and everyone's post. Click it and report it. MOZ is targetted for,duh, it's high PA/DA.
Structure like a theme dont change the content, so yes you can safely change that. The URL's will remain the same as well so that shoud'nt cause an issue at all.
No that's content. Adding a page is extending your site structure.
The string 'get_bloginfo('description')' spawns the blog description stored in wordpress under settings. But that shoud'nt cause issues with different setup descriptions per page while using a SEO plugin on wordpress. It's more of a theme issue i think because normally that shoud'nt happen.
I woud'nt worry alot about it either; google tends to ignore the description sometimes too and focusses on the actual content on page.