Regarding "Kucha", there is an interesting story:
Sri Sita delivered a male child in the hermitage of Sage Vaalmiki.
He was named "Lava". One day, Sri Sita entrusted Lava to the care of
the Sage and went to have her bath in the nearby river. On her way
she saw a few monkeys which were jumping hither and thither hugging
their young ones. On seeing this, Sri Sita was smitten with remorse
that while even the monkeys were so concerned about their babies,
she herself had not even an iota of such concern for Lava and
hurried back to the hermitage and took bay Lava with her. At that
time the Sage was in a trance (Samadhi) and did not see what
happened.
When he woke up he noticed that the baby entrusted to his care was
missing. Hurriedly, he made a baby out of Kusa grass and after
breathing life into it (praaNa pratishTai), left it in the cradle.
When Sri Sita returned, she was surprised to see another baby in the
cradle and enquired the Sage about it. The Sage narrated the whole
incident and told her "I have named him as "Kucha". Kucha is also
your son as much as Lava. Take him"
(Source: Kathaa sarit Saagaram, Alankaaravateelambakam quoted by Sri
C.R. Srinivasa Iyengar Swami at Page 33 and 34) of his Notes on
Uttara khaaNDam)
Sri Sita delivered a male child in the hermitage of Sage Vaalmiki.
He was named "Lava". One day, Sri Sita entrusted Lava to the care of
the Sage and went to have her bath in the nearby river. On her way
she saw a few monkeys which were jumping hither and thither hugging
their young ones. On seeing this, Sri Sita was smitten with remorse
that while even the monkeys were so concerned about their babies,
she herself had not even an iota of such concern for Lava and
hurried back to the hermitage and took bay Lava with her. At that
time the Sage was in a trance (Samadhi) and did not see what
happened.
When he woke up he noticed that the baby entrusted to his care was
missing. Hurriedly, he made a baby out of Kusa grass and after
breathing life into it (praaNa pratishTai), left it in the cradle.
When Sri Sita returned, she was surprised to see another baby in the
cradle and enquired the Sage about it. The Sage narrated the whole
incident and told her "I have named him as "Kucha". Kucha is also
your son as much as Lava. Take him"
(Source: Kathaa sarit Saagaram, Alankaaravateelambakam quoted by Sri
C.R. Srinivasa Iyengar Swami at Page 33 and 34) of his Notes on
Uttara khaaNDam)