Multiple level of appraisers scenario

Hellow Guys,

We are impleting Objective setting and appraisal in EHP5 with NWBC.

We have multiple participants (approvers) in appraisal cycle. Immediate supervisor in org structure is responsible for final rating. Once employee fills self appraisal and is rated by immediate supervisor it flows to further level of approvals until it reaches CEO and then HR. Number of approvers depend on org structure which is not fixed as it depends on employee and org structure. These approvers will not have access to modify anything but just approve and reject. This has to be done in sequence.

Since all approvers have to be done in a sequence like immediate supervisor then its upper supervisor (may or may not exist for every employee, this can be chief position for higher department) then Manager (we have already defined hierarchy code in system to identify managers) then CEO then HR.

I think that this can be achieved by including all approvers except immediate supervisor as further participants. We have to maintain a status for every further participant like approval by supervisor 1, approval by supervisor 2, approval by manager, approval by CEO like that. Manager should only approve once it is approved by supervisor 2 etc.

Below are my queries:

1. But my query is how to maintain sequence in further participants, in standard we can not maintain sequence, now in system all further participants can access the document after final appraisal and are able to approve and reject it in any status. So how should we maintain this restriction?
2. Second is, creation of appraisal documents. Since we have multiple level of approvals and thus multiple status depending on
   org structure of employee. Do we need to create separate appraisal template for all possible scenarios and do a custom development for creation of template though phap_prepare_pa or there is some other easy approach to do it.
3. There is another query, where in CEO is last appraiser before HR. requirement is that, CEO can not go and open each and
   every document and approve/reject it. So client want mass approval functionality for these documents. Where in CEO will just see the final rating of employee and approve or reject it. Do we have any mass approval functionality in standard.

Guys
please advise, if above mentioned scenario can be achieved in standard or we have to got for custom development and what should be the approach.

Thanks in advance.

Thanks

Abi