«حَتَّى لَاحُوا كَأَسْنَانِ الْمُشْطِ فِي الِاسْتِوَاءِ»
Until they appeared equal like the teeth of a comb.
Ka-asnān al-mushṭ explicitly marks a comparison. The phrase fī al-istiwāʾ states its relevant feature: equality. The travellers are compared to the teeth of a comb in the way they stand together.
Their bodies are not being declared identical. The comparison emphasizes an aspect of social relation, and the translator should retain that limiting feature.
Question of interpretation: equal in what respect? In the specifically stated aspect, not necessarily in height or appearance.