I hope this finds you well. I just saw this and thought I'd reply. I don't know if you know this but there are 2 types of kefir: Milk kefir and water kefir (aka, Sugar kefir grains or SKG.) I looked at your kefir packages and you have milk kefir.
I make water kefir every couple days (just made 18 bottles last night and have far too many grains. LOL) And though I've not yet started the milk kefir journey, I'm very familiar with it as I researched both before choosing what to start with. In case you would like to get some SKG, I got my grains on eBay and my minerals online at Earth Shift Products.
Without going into too much detail, milk kefir feeds on the sugars & proteins in milk and SKG feeds on sugar. Though they are both called kefir and they both create probiotics, they are actually two very different living organisms and, as such, are not interchangeable. Milk kefir will die if it had to feed on Sugar water for it's sustenance and visa-versa.