Yes Ankit
let me explain u in brief
1) Date field will be displayed by default for any leave. because we make settings in V_T554S_WEB as start date as future or current day. and also for each Absence we maintain a quota as days/hours so system takes date as mandatory field & it will show the same in ESS Leave request. and If u still want to make that dates to be hidden for that one Absence then it will be really a big task for ur ABAP team. I suggest u to convince ur client on this.
2) The Idea behind to make the dummy absence as blank is to make users to select their suitable type of absence from drop down menu. but not to apply the blank leave type also naively & if they still try to apply also the system is restricting.. right!!!! and there is no point to worry on this blank leave type as this was not given by client & it has no impact on the business.
Normally the counting rule error comes when u don't configure this steps
Deduction rule absence quota
Deduction rule to counting rule
counting rule to absence type
Hope I made it simple & clear
Cheers
Pradyp