Are these guaranteed? NO WAY! Nothing is guaranteed.
I do not know these. I have never heard of these so-called techniques. Certainly, they are not SEO efforts, but have the feel of some sort of gentle and kind manipulation to gain backlinks to me. Certainly, as much as you can, you want to help people with their website. And out of kindness, they may link back to you. That is a good thing and that appears to be what these ideas are about. Go for it! There is nothing wrong with kindness and helping people. That is what we do here. I highly recommend it!
I just kind of warn you that most owners of broken sites are resistant to change and help. But there are enough that will appreciate your efforts and you will at least find it a rewarding effort even without a backlink.
Here is what you are missing and MUST(!) remember about backlinks. They must be relevant and from content page to content page, from a site with value, and pages that have similar or complimentary content topic. Otherwise, they have little real value.
I suspect you are reading as much as you can about SEO and getting rather excited about the possibilities and ideas. I warn you that most of what you read is absolute garbage. REALLY!! Backlinks are hard to get. Any idea that works for you to get a backlink would be worth considering. But I warn you about quality and relevancy of any link. It only takes a few high quality and well placed links to make your site take off. Honest. Would I lie to you? It only takes a few more moderate quality links and well placed links to do the same thing.
Organic links are the best. These are the ones you do not create. Of course there will be plenty of sites creating links to your site that will be junk, but generally speaking, these will not hurt you. Google and Bing understand these links and simple ignore them to a point. But the ones that are made by people who run good quality sites and not machines is like finding a gold coin every day. This is what you want.
The VERY BEST(!) SEO tactic is creating high quality and unique content that people will want to link to. It must be compelling and must be on a topic that people want to know about. Become a think leader in your field and seek new ideas and new discoveries of your own. Look at things differently and with a fresh look. Do not parrot the same 'ole same 'ole horse swaddle. This does not work. If you can make compelling content, it will take time for people to discover it, but you can help it along. I am not a Facebook fan and I do not follow Twitter at all. But I do recommend Twitter big time! Use Twitter to drive valuable organic links to your content. It will take time to gain a following. All of this could take as much as a year, but your site will catch fire if your content excites readers. And you will be unstoppable.
I also recommend using Google+ and LinkedIn. These too will drive your site to success.
Here is a secret I will share. Websites are not only about information, but personalities. Be personable and explain things well. We do not just choose sites for their content, but for the person who wrote them and we got to know. It is always about personalities and people we share an affinity with. The web is really a social tool more than anything. Keep this in mind and seek what you can do that puts YOU out into the world that is content centric.
The last secret I will share with you is extraordinary patience. You MUST(!) have it. There is no fast way to the top or even the middle. There are no short-cuts, no magic buttons to push, no magic combinations of just the right things to do. It is doing the hard work of content creation and marketing (yes I said marketing) your content. It is always about content. Any effort short of this and gain found would be temporary. What lasts is valuable content that people like and it will take significant time to catch up with those who have come before you. Be patient- very patient and do not be in a hurry. You will benefit from your patience in the end.