AWS doesn’t offer an Australian region. Galaxy is just PaaS using docker and AWS. Heroku uses AWS also. Likely whatever framework/platform you choose will have the same issue.
Bluemix has better regional support for you. It is truly awesome although I have only played with it and ok I used to work for IBM Australia but promise no bias. Other hosting solutions are available.
Are you getting serious latency build up? Are all your users in Australia? Why use AWS at all? Have you thought about hosting yourselves? There are numerous advantages eg. cost, performance and security over just eating up whatever docker dogfood is available on AWS.
On the issue of your company’s framework I would say simply ‘Eggs’, ‘Baskets’. Beware lock in. Embrace a range of technologies. Keep it agile and open. There is nothing wrong with having a diverse ecosystem. I expect you will have Go and Python or Ruby and some C and BASH and who knows what as well as Meteor. Why limit your toolbox to one albeit very nice multi-tool? What advantages are conferred by having a single framework? They are probably imaginary and you may find that you are doing premature optimisation.