Postponement of challan submission by acb

 (1) whether ACB can stop such challan submission merely on personally showing stay order without official receipt without becoming party in stay order as ACB is not party in stay orders.

Stay order is operating.  Hence, ACB has to comply it.  But  there is some connivance between the accused and the ACB and hence ACB didn't show up in HC proceedings.  So, in the capacity of complainant become a party and intervene in HC proceedings and expose that how accused got away with stay order without giving prior notice to the ACB as well as complainant.

(2) Necessity of prosecution sanctions of all eight persons for challan submissions

Whether sanctions  are required or not in respect of eight persons completely depend on the facts of the alleged offences and the designation of the accused and whether they did those alleged offence during the course of their duty or not.  There is a vast case law decided by SC on this particular point.  At what stage sanctions are required also, the SC decided in several cases.  But it is always preferable to have sanctions at the time of  filing challans.

(3) exemption in such stay order without making complainant as respondent against whose FIRs, challans to be submitted

Unfair.  But it happens.  So approach the HC and become a party and challenge the stay orders.

Thanks for enriching reply. As suggested by you to become party in the writ, I tried to search format for filing applications to become party in civil writ but could not locate. 

Please provide format for filing application to become party in civil writ.