Anatomically, it is possible to pull off. The costume would, of course, still have to adhere to the CRLs. It would pose a challenge and be quite the undertaking (particularly the helmet).
Remember that:
Non-humanoid aliens are allowed. However, not all species will be allowed due to the reality that it is not physically possible to execute a quality Mandalorian costume with some species within the Star Wars universe: some species would not be able to wear Mandalorian armor such that it would sufficiently meet the CRLs.
Armor and soft part modification may be necessary based on your choice of the alien species. The kit should look like it would fit the specific species. As an example, the helmet of a Twi’lek Mandalorian should be modified to accommodate the lekku of the Twi’lek species. Alien kits will be judged on a case by case basis.
It is a project that would require a lot of creativity and skill in execution. It is also a build that we would highly recommend working closely with the clan's Ruus'alor and regional Ruus'sol to execute properly.
