We have got a reference from IBM team that IBM WCM contents can be crawled by
any external search engines using search REST API exposed by Portal. However due
to lack of experience in BCS, I need your help in assessing if this is possible
to achieve or not.
Kindly help me understand if we can achieve this in SharePoint and if we need any custom development/special customization related to BCS based crawling.
IBM WCM contents can be exposed using atom seed/feed. However SharePoint does not have built-in capability to parse and crawl the Atom seed. You may have to develop a custom connector or a custom iFilter for parsing through the Seed.