I am not very good at identifying mutations, but I can tell you a little about the possible outcomes of a pairing between a male slate and female creamino peach faced lovebird.
First, let's talk about base color. Both slate and creamino are "blue series" colors, which means that in addition to other visual mutations, the bird must have a parblue mutation - either Aqua (Dutch blue), Turquoise (White Faced Blue), or AquaTurquoise (Seagreen). A creamino is parblue and ino. If the bird has green base color, it would be lutino, instead of creamino and much more yellow. There is no true blue in peach faced lovebirds, so there are no true albinos (solid white with red eyes). Of the three blue colors, Aqua has the most yellow color and Turquoise has the least. AquaTurquoise, as the name suggests, is a mix of Aqua and Turquoise, so it is in the middle. So if your creamino bird is very light colored with a white face, she probably has Turquoise as her base color. If she is more yellow with pink cheeks she probably has Aqua.
Slate color comes from combining parblue with two dark factors. In a green series bird, one dark factor will produce medium green ("Jade") and two dark factors will produce dark green ("Olive"). In a blue-series bird, these colors are called “Cobalt” and “Slate”, respectively. However, because parblue also comes in three different shades, there is a decent amount of variation in color for cobalt and slate birds, depending on if the base color is more green-colored (aqua) or more blue (turquoise).
If your bird is olive green/gray, then he might be aqua with two dark factors. Or he might be a green series bird with one or two dark factors and violet factor.
For the sake of simplicity, let's say that your girl is aqua and ino. And your boy is aqua and double dark factor. No other mutations.
In that case, all female offspring inherit aqua from both parents. All male offspring will be aqua split to ino. All offspring will have a single dark factor. So all of the babies will be cobalt (medium blue) in a greenish color.
If your male is aqua and your female is turquoise, the offspring will be AquaTurquoise (plus dark factors). If both parents are Turquoise, all offspring will inherit turquoise.
If the male is actually green, not parbblue, then all offspring will be green, split to blue. If he is green, split to blue, then half the offspring will be parblue and the rest will be green split to blue.
If your male is split to ino, you might see some creamino offspring. If your female has one or more dark factors, then the babies will be all dark (if both parents have two dark factors) or a mix of shades.
There also might be other hidden genes which could affect the outcome - for example, your ino female might be carrying violet factor or other mutations that are masked by ino or your male might be split to other recessive mutations. Without knowing more about their parentage, it is impossible to rule out entirely.