Hello,
1. The marriage is valid since it was solemnized after obtaining the divorce decree.
2. The High Court can still grant alimony in the Appeal. For maintenance, have you taken proceedings u/s 125 CrPC. If you had filed 125 CrPC case, and you could not succeed in that, then file a revision before the High Court to get maintenance.
3. Regarding alimony and maintenance your remedy is filing appropriate proceedings under 125 CrPC, Domestic Violence Act, Hindu Marriage Act. And for return of Dowry articles, you need to file a case under section 498A, 406 IPC. However you need explain the delay in case you haven't filed the above cases till date.
Regards,
Nishant