Suggestions for flavoring

I have a 5 gallon batch of high ABV mead which has been sitting for a year to develop flavor. This has unfortunately not happened. I tried to backsweeten without success. I'm now considering splitting it into 5 batches and adding flavor to 4 of them, while letting the last one sit longer.

The flavors I've considered are:

Lime
Vanilla
Orange peel and Cinnamon
Raspberry
Red Currant

The method I've used before has been to add the falvorings to a mueslin bag and let it sit for two weeks.

Would this be a good idea? I won a competition with a mead I flavored with orange peel, cinnamon, cloves, and ginger in 2011.

All of those flavors sound good, as does your procedure.

That's good to hear any suggestions on amounts per gallon? So I don't go overboard

Lime - Don't think you can really overdo this one. a 50/50 mix will give you an alcoholic lime-aide, but that doesn't sound too bad.
Vanilla - One vanilla bean per gallon?
Orange peel and Cinnamon - refer to a JOAM recipe
Raspberry - I'd go with at least three pounds of fresh rasberries per gallon
Red Currant - Don't know much about red currants, as they are not common in the US. But I'd assume 2-3 pounds per gallon

Thanks