There are no any extraordinary things to do in order to make it work with rEFInd, e.g.:
“Boot with optimized options” “rw quiet bootsplash.bootfile=bootsplash-themes/manjaro-mi/bootsplash cryptdevice=UUID=350a09b6-89b9:cryptlvm:allow-discards root=/dev/mapper/ManjaroVolGroup-root rootfstype=ext4 resume=/dev/mapper/ManjaroVolGroup-swap add_efi_memmap initrd=/EFI/manjaro/intel-ucode.img initrd=/EFI/manjaro/initramfs-%v.img”
The example above shows necessary option for refind-linux.conf along with another options. It's just the same as for /etc/default/grub.
Do note that bootsplash does not support entering passwords for decryption like plymouth does. If you have smth encrypted you'll have to hit Esc during bootsplash animation and enter you password in console prompt.