What would be best for my 12 month old baby nutritionally - toddler formula (s26), growth milk (parmalat growth 1+), or normal cows milk?

Depends: The popularity of late stage formulas is more an effort to broaden the sales base than a nutritional need in kids. Breast milk or formula is important for the first year but becomes less so as growth slows & the kid has accepted a broad nutritious diet. In a kid with chronic illness, poor growth, or odd dietary habits I may stay with a toddler formula. Most kids will not need one.