Upgrade the site to OpenCart 2.2

Simple upgrade project for experienced developer. I am searching for someone with attention to detail that would truly make an error free upgrade for us and make sure - THERE IS NO ERRORS OF ANY KIND ON OUR SITE. We upgrading it since the current speed of the template (also professional site) is not that great. We are hosting on dedicated server, have no huge pictures, not that many product either but the speed CSS, JS files that load the site are insane and it slows the site on any mobile device. We tried to fix them but they are in the platform itself so it is best to upgrade to fast template that is far more advanced then current one we use. It is a live site so once you start the project the upgrade needs only (migrate to Opencart 2.2 and then new CosyOne template) to be done in few hours since we have users on it all day and night long. 1. BACKUP: Do the backup of the current site - just in case something goes wrong. 2. OPENCART UPGRADE: Upgrade OpenCart site 1.5.6 (current one to) OpenCart 2.2. 3. UPGRADE TO NEW TEMPLATE: CosyOne 2.0 (Opencart 2.2). (professional template that loads super fast on the phones and it is error free, optimized for every browser. Template has currency converter and few languages available so want to choose few - (Russian, Spanish, Dutch) 4. SITE SET-UP: Set-up of the site: all stays the same: pages, categories, info pages should be identical as on 1.5.6 since layout will be exactly the same. They should transfer automatically since they will be the same as current. 5. SEO PACK: Upload SEO Pack extension (free upgrade) for Opencart 2.2 (we currently have it on the site but want to upgrade to new version. Some SEO features are already in the platform so maybe not needed to upgrade. 6. MEGAFILTER: The CosyOne platform supposedly has a MegaFilter in it but we not sure, if yes we will use filter that it is in the template. 7. GOOGLE: We get Markup [login to view URL] Error now - but it is most likely due to current template. New one should have no errors, but needs to be checked. 8. SSL: Fix SSL certificate on images or move them to correct folder. We have 2 SSL certificates on 1. [login to view URL] 2. SSL on [login to view URL] - (secure check out) I never seen anyone placing SSL on images on any site but we had to do it since on the current template OpenCart 1.5.6 we were getting messages from customers who use the phone that the site is not secure and images are showing as insecure. I was told by webmaster that I need to move pictures to standard folder images/domain so they will be secure. I honestly have no clue who put them in other place then standard. The certificate is due to expire on 07/27/2016 but I don't think we need one for images, so we need that fixed. So that will be it...we will set milestones -2 in total on freelancer and then release the payment after completed step. Final step will be released when SEO on goggle will be working great and we will see no errors. It takes time for them to index so final payment will be released then. new template, 2 extension, all the passwords will be provided once project awarded.