EZ Fulfill has a pre-set template that's very similar to the templates MassFulfill provides.  You can upload the template files you used with MassFulfill with EZ Fulfill.

However, there are a few differences with some of the templates, mainly when marking orders paid, adding notes and tags. 

When adding notes or tags, you need to provide the notes and tags with the orders you are fulfilling.  EZ Fulfill will allow you to add notes and tags if you upload an order's tracking number or mark the order fulfilled.  Currently, we don't allow you to upload notes or tags without fulfilling orders.  You can read our documentation on fulfilling orders tags and adding notes.

When marking an order paid, you will need to select the mark order as paid flag on your data feed setting.  This feature also works when fulfilling your orders.  Similarly to notes and tags, you can not mark orders paid without fulfilling the order.  You can read our complete documentation on how this works here.