Finally...! I am successfully able to boot guest vm in secure mode, attached the screenshot for the same. Secure boot works fine with out enforcing keys from UefiShell.iso, As suggested i have used the image fedora-29-efi-grub2-x86_64.qcow2.xz. However i have learnt many new things from these conversations. A big 'Thanks to you' for your support and resolving my questionaries.
Though I am yet to learn many things about 'UEFI' and it's different specification this will be good motivation for me to proceed with further.
Regards,
Pavan.