Wht % that a type I diabetic mther and celiac father would have kid with one or both conditions?

Unknown. There is no way to put a number on the chance of having one or both of these conditions. Genetics definitely increase the risk but there is no guarantee that the child will get one, both or none of these ailments.
Roughly 5% and 20% If a male has T1DM then there is a 5% chance a child will develop it. If a primary relative has Celiac there is a 20% chance. These are population based and many other factors are at work, most unknown / unproven. While high on the population level the main thing to note is that it is MUCH MORE LIKELY that your child WILL NOT develop either. I would not recommend special precautions or testing.