i have just taken up slabs from my back garden and broke up all the concrete hardcore now i have dug a massive hole and buried all the hardcore (on a budget didnt want to get a skip) all the soil that i dug up i have now spread all over the garden with a bit of clay here and there but not to bad

question 1. do i need to flatten the soil as in roll it or do i just lightly rake it over before i put the grass seed down.

question 2. what grass seed do you recommend for this type of soil (clay ish) and it has to be hard wearing because of children and dog but want something that also looks nice.