OKTA MFA flow , Please help

We are planning to implement OTP based and Biometric Based login functionality.

I have checked the below docs

https://help.okta.com/en/prod/Content/Topics/Security/mfa/mfa-home.htm
https://developer.okta.com/code/javascript/okta_sign-in_widget/

Few Questions :
In our login page we don’t want user to enter Password. Instead want to show the OTP Selections page based on configured factors

What all OKTA API we need to call to Authenticate the user

Does “Password” is mandatory for all “AUTHN” service call i.e. {{url}}/api/v1/authn
What would be the exact API call to implement this
· User enter User ID – will get the OKTA Unique ID. Call {{url}}/api/v1/users?search=profile.email eq “test@test.com
· Will retrieve all FACTORS details. Call {{url}}/api/v1/users/{{userId}}/factors
· User will select Mfa type and will proceed with MFA
a. Call to send code {{url}}/api/v1/users/{{userId}}/factors/{{factorId}}/verify
b. To Verify {{url}}/api/v1/users/{{userId}}/factors/{{factorId}}/verify

when & how we will get OKTA SSO Session Token to proceed with OKTA Authorize API Call ?

regards,
Vaskar