Leave recall or cancellation for approved leaves in EHP 6, Different approvers for different leaves in ESS

HI Friends

We are implementing ESS MSS on ECC 6, EHP 6 and NW 7.3. I had some issues here, can someone please clear for me

1. Do we have a leave recall or Leave cancellation option for the approved leaves in ESS.
2. For paid leave, flag option to be available to notify employees applying for leave if they need to earn the leave allowance. How to do it on Portal.
3. We had a condition where

• Annual Leave to be approved by Line manager
• Maternity and paternity by C&B manager
• Study Leave by L & D manager
• Trade conference leave by ER manager

While defining the rule groups we will configure determine next agent field. Then how can I configure different approvers at different levels in Org unit for different types of leaves under same rule group. How can workflow customization help me here.

I would be very thankful if someone could help me out in the above issues

Thanks & Regards

Ravi