some questions regarding the preprocessing steps

Hi experts,
I am using DPABI to perform Functional Connectivity. I have some questions regarding the preprocessing steps.
1)Does Preprocessing steps order matter for performing Functional Connectivity analysis? and which are the recommended preprocessing steps? because I have seen different groups used different steps order (e.g., FunImgARWCSDFB, FunImgARCFWS, FunImgARCWSF, etc)
2) If I write "0" at slice number and reference slice boxes, will DPABI choose the middle slice based on the inputted slice order?
3) Should I exclude the subjects' data with head motion above or equal 3.0mm?
4) Some of my T1 data quality seems not good. How can I know that if the data can be used or excluded?