Yes, SEO is very important for a new business as if someone is not able to search you over the search engine they will not come to your website and if your business is E-Commerce related it is really important for you. I would suggest you check ogscapital.com/article/insurance-agency-business-plan/ as it will give you a rough idea as to what all things are required for a successful business startup.
Yes, online strategy is very important to run the business fully. It is the way of marketing online to know about your products. It is also important to handle clients properly. Because at early your may not able too co-operative with the customers. So you may try the Customer Service Call Center to do the handling of the customers. You may think that it's an extra expanding. But no, one customer can bring many customer with in no time, if he ore she get the proper help from you. Tthey are the main asset of your business to run up easily. And SEO can bring this type of online customers more than you can handle them out.