It is possible, but most likely not much to make a difference.

both programmes are about design. however, both are focusing at a different scale. in interior design, the design is pretty much defined by the kind of architecture that was given to u. u dont deal a lot on structures or social issues of the users. in architecture, u have to deal with everything. the scope and depth are bigger.

credit transfers wont make much difference because there are many more things that u havent learned or covered in interior design diploma that has to be covered in order to proceed in architectural degree. so in the end, u might be transferring a semester's worth of credit at most, but not enough to skip a whole year.

yes. u will only take part II if ur part I is already accredited. or in cases where people study both parts I and II overseas, they can just finish off straight from part I to part II and only comeback to sit for the exam ONCE.

usually they will look into what u have done during ur studies (studio projects) and if those have covered all that needs to be covered according to LAM requirements. if it fulfills and u manage to answer their questions (in interview format), then u get the license. if u fail, then u will do the design project exercise (about 3-4 months) and then sit for the exam again.
why not opt for diploma in architecture at other places? i mean in regards of architecture education, polytechnic diplomas are highly commended as compared to IPTS diploma. means better chance of getting into IPTAs for degree, and cheaper as well.

My email is azarimy@gmail.com, although i prefer less private discussions to be held here, so that it could benefit others one way or another.