There is no golden hammer in RESTful design.. you should drive your
decisions by the characteristics of your business model and also
considering the size of your data ..
all options you quote are valid.. and you should always look for the
fastes response time as possible for the full chain of calls to
complete a use-case...
So, if the parts are already spread over the web, to return a
collection of link may reasonable.. but if the data is in your
database, you should balance the number of calls with the size of the
calls to know what is best in each situation.. you can mix both
without problem, avoiding rigid concepts about "best practices".
test it.. do a prototype, establish your own benchmark before to
follow magic recipes..