Build an Online Store

I need an advice from an expert with experience in creation of big open source social network projects. We are looking to create a social ecommerce network for seniors. I need a detailed advice on what tools , framework and plateform to use to create a SOCIAL ECOMMERCE NETWORK =============================================== this combo or tools or framework needs to meet all of the conditions below if possible: * affordable * Easy to use * Easy to Maintain * flexible * very scalable (that comes with cassandra database or can be work with it ) * open source * customizable * very stable * Fast and light even with growth * Multi Vendor , Multi Store * where it can integrate or exchange data to other markets like amazon and ebay The top picks that we thought of was: ***Buddypress + woocommerce ***[login to view URL] with [login to view URL] market place ***[login to view URL] ( [login to view URL] ) but seems to lacks powerful ecommerce but maybe could integrate with outer ecommerce also ***[login to view URL] and Magento ( seem to be really good combo) Others kind of great but not much support it seems: ***[login to view URL] but not so much plug ins and community and no strong ecommerce *** [login to view URL] no strong ecommerce it seems and the exhaustive list here of some i don't even know : [login to view URL] So if you have lots experience in creating such a plateforms and know the ins and outs of what is the best that meet the above criterias please let me know so we can learn from you experience... The report can be on a chat with maybe 2 hours of expertise on skype if you take on the project of sharing your advice and input. Paying 50 USD per hour. I will look at your previous history of projects to see if you have some projects that match that or even better send me the links of the projects you did in social network so that i know that you walk the talk. Will save me time in order to pick the right candidate. Thanks to all . And even if you are not picked i thank you for you time in advance and your kindness in helping others. Yours Truly Kevin aka Z◘vñiA