Hi there, karthikrkaranth.

I appreciate you for presenting your concerns orderly.

Since your concerns fall on the integration side, I'd recommend posting these questions to our Developers page. API or integration issues are handled by our software engineers. 

They're the best support that can guide you to resolve these matters and provide you with the correct answers about the procedure and the integration process. 

Also, if you have some How do I concerns with QuickBooks Online, you can visit our Help Articles page.

Keep me posted whenever my assistance is in need. Know that I'm just a post away.