- Are total process records = inserts + updates + deletes +discards + ignores?
Generally total process records = inserts + updates + deletes +discards + ignores

- Are update collisions is part of updates ?
Yes

- Are delete collisions is part of deletes?
Yes

- Are total successfully process records = inserts + updates + deletes?
Yes

- Can HANDLECOLLISIONS handle ORA-00001 error?
No, HANDLECOLLISIONS can not handle ORA-00001 error. This error is an unique constraint violation error.
HANDLECOLLISIONS control whether or not replicate tries to resolve duplicate-record
and missing-record errors when applying SQL on the target.
These errors can occur during an initial load, when data from source tables is
being loaded to target tables while Oracle Golden Gate is replicating
transactional changes that are being made to those tables.
You can read more about HANDLECOLLISIONS and NOHANDLECOLLISIONS in Oracle