I would suggest adding 3-5 tsp of moringa powder to the iron syrup to start. The shelf life would be the same, around 6 months to a year if kept in the fridge.
Here is a link to the registered herbalists with the Ontario Herbalist Association https://ontarioherbalists.ca/find-a-herbalist/
This is a good place to start your search. If you can’t find anyone close enough on their list you could get in touch to see if they can recommend anyone else. Or another option is that there are many herbalists that do online consultations as well.