Hello.
It's a very interesting project this one you have started.
I have solid background on software development principles, and for project management I like to follow Scrum.
I have experience using Spring for web services development. wich gives the extra bonus of simplifying the integration with so many products which comes Spring-enabled out of the box. Anyway, Spring is just a solution, so I can use any other support technology you choose.
Lastly I have been on the BigData world, using tools like Voldemort and Cassandra. About ORMs, MyBatis is an excellent alternative to Hibernate.
Mockito and test-driven development are truly life-savers for long-term projects. I also use Maven for dependency management.
You won't see any star or reference on my account because I am very new to Freelancers. But my first job dates back to 1997. On last years I have developed projects for telecommunications and tourism customers.
I will be very glad to provide my support to achieve your goals, and I am very confident that I will finish on schedule.
If you have any questions, please let me know.