Hi @0203amit,
1. Can we use AJO standalone? I mean without AEP - Adobe Journey Optimizer is built natively on top of the Adobe Experience Platform. If you're asking Journey Orchestration that doesn't have ESP capabilities. For more info take a look at this documentation: https://experienceleague.adobe.com/docs/journeys/using/starting-with-journeys/about-journey-orchestr...
Also sharing this community thread to have a look at it - https://experienceleaguecommunities.adobe.com/t5/journey-optimizer-questions/ajo-integration-without...
2. What are out of the box messaging channel we have in AJO. - Email, SMS, Push, In-app, Web, and Direct Mail.
3. Can we use below channel through AJO - Take a look at this conversion API (https://exchange.adobe.com/apps/ec/108589/sinch-conversation-api-for-adobe-journey-optimizer)
a) Line
b) WhatsApp
c) Telegram
d) Facebook messenger
e) In app messages
f) WeChat
Thanks, Sathees