I use Splenda in my son’s Elecare. He has been on Elecare for two months now. This is what our ped GI recommended for us. I know that Neocate makes flavoring for their formula. You might check the website.
If you use the Splenda, just use the smallest amount that it takes for your little one to drink the formula. We use 1 packet per bottle. I sarted out using more, b/c it took a couple packets for my ds to like the Elecare, but I have weaned him down to just one packet. I buy a box of 1,000 packets at Sams Club for about $20.