exactly alike (in appearance); like two peas in a pod; (practically) identical; spitting image (of); carbon copy (of)
nickname; alias; pseudonym; pen name; nom de plume; other name
immediate reply; quick answer; ready agreement
one or two; a few; small number
one of two (possibilities, alternatives, etc.)
two at a time; two by two; in twos
two at a time; two by two; in twos
pigtails; bunches; two ponytails; angel wings