CreLoaded Site Mods , SEO Optimazation and Bug Checks

Have a CreLoaded Site (Currently Live) Need the following: Checked for Html Bugs and code errors. The site runs fine but some customers have issues checking out , if an order is declined and they retry and successfully authorize their order a order number is not created. Optimize the sites Meta Tags for Search Engine Optimization , as well as provide feedback to make adjustments to site for better search engine results. Assistance with E-Check Module : Currently have echeck module contribution installed , once information is filled , order is completed but no information is showing up on Authorize Net end , no clue whats going on , no error messages. I ran a SEO tool and found some minor errors that need to be checked for compatibility for Opera Based Browsers. Assistance in this area also requested. Overall the project is some minor bug fixes and optimization , need quick and professional. Remember site is live and I need minimal downtime. Thank you for your time.