Support on Drupal based website (implement SEO recommendations/Google Tag Manager))

We have recently launched a Drupal based website: www.allergenmd.ca. The website was developed by an external agency. Unfortunately the agency is not able to provide follow-up and implement the necessary corrections. Here's a list of outstanding items. We would like to agree on a fixed price for these issues. Moving forward we are looking for a trustworthy business partner for ongoing support (hourly rate). SEO Issues: Issue #1: There is a rel=canonical tag on the homepage (<link rel="canonical" href="/allergen-md-sublingual-immunotherapy-permanent-allergy-relief" />). This tag basically tells search engines: "The homepage is a duplicate of the page /allergen-md-sublingual-immunotherapy-permanent-allergy-relief" - which is an unnecessary webpage that doesn't benefit from any internal or external links. Proposed solution: Remove the rel=canonical tag on the homepage. By the way, there isn't any duplicate content on [login to view URL] - so I would also recommend removing all rel=canonical tags from all webpages. Also, the webpage /allergen-md-sublingual-immunotherapy-permanent-allergy-relief shouldn't exist - remove it and redirect it (301 redirect) to allergenmd.ca. Issue #2: Webpages starting with "www". are not redirected to webpages without "www.". Some users and websites still type "www." before the domain name - over time, pages with "www." might generate links and social signals. Proposed solution: Add a 301 redirect rule from [login to view URL]* to [login to view URL]*. Issue #3: There are 2 H1 tags on every webpage - one is correct (title of the webpage) and the other is unnecessary: <h1 class="element-invisible" id="site-name"><a href="/" title="Home page" class="active">Allergen MD</a></h1>. Proposed solution: Remove <h1 class="element-invisible" id="site-name"><a href="/" title="Home page" class="active">Allergen MD</a></h1> from all webpages. Issue #4: There are 2 unnecessary H2 tags on every webpage: "Menu" and "Contact Us". Proposed solution: Remove H2 tags on "Menu" and "Contact Us" from all webpages. Issue #5: There aren't any H4 tags on the webpages - but they could be useful to structure the content. Proposed solution: Create CSS for H4 Issue #6: Meta tags (Description) are not being published Issue #7: Generation of automatic XML sitemap, generation of automatic sitemap page for end user Issue #8: Homepage <title> tag updates are not being published Tracking/Google Analytics/Google Tag Manager Issues: Implement Google Tag Manager Datalayer according to specs (including automatic insertion of variable such as language, city, page URL, etc) Miscellaneous: Content is partially hidden by nav bar when linking to anchor links