Possible Clues:

• It's somewhat strange to hesitate in the middle of crossword for newcomers
• Morphing is for green aliens
• Craft is for green aliens
• Newcomers hold sway in rival Resistance at the start of struggle
• Ferries go off carrying new people from abroad?
• Strange tails on three particular reptiles from Aliens
• Outsiders
• They're not familiar with what's contrary to what's already here
• People from abroad get undeclared jobs