Wow! you must be super mum! Triplets and you still managed to do a manual Doman program! My hat goes of too you.
Firstly don't stress your time effort and money were not wasted. You babies did learn. They just havnt yet learnt how to show you what they learnt. Some kids take longer than others, once they start, due to the fabulous background you have layer, they will zoom through beginning reading stages. It is all in their brains just waiting to connect. That is what my children mostly did. Stored it up and then exploded.
So what next you ask?
Their age matters. They are heading into an age where phonics will make sense for them. You can teach them using phonics and sight/whole words now
continue with preschool prep. Many of us aware by it for transitioning from single words to reading books. Kids are not confused by multiple methods. You could add in little reader now and still get a good deal of use from it. It also includes phonics instruction and its a LOT easier than making word cards.
try also readingbear.org and see how they like it. It is often the missing piece of the puzzle and its free!
Now little math....well honestly I think you have missed the boat on subitization. You could teach them skip counting and numeral recognisition with it but frankly I think your money is better spent with......
Little Musician! You definately want this one and right now! Your kids will LOVE it! And so will you and I cannot imagine a cuter picture than a group of triplets arguing about the tone of the water dripping from the tap into the bath
get it you won't be dissapointed.
Now languages. Since you opted out of LM you have room for a language but I would get the routine going first on the others and then add it in if you can. Using an iPad might help. I used to show my son his lesson each time I buckled him into the car. With three I imagine a captive audience would be even more important!
Remember to count and skip count around the house and show numbers to cover their preschool math.
Also if one is more receptive teach only that one at that time. Even if one of you kids learns to read early or that could be all it takes to tip the scale on the other two.
Triple tantrums! Oh what fun! Good luck.