I don't know if anyone could answer all of these questions decisively because we all fail to measure up from time to time. Even if these could be answered, there would be a whole new list of questions brought up.
I think the problem we have in understanding "holiness" is that we tend to think of "holiness" as a state of being. Its a place that we arrive oneday. But, in my view, holiness is more of a process that begins when we begin to follow the Lord. 2Cr 7:1 speaks of "perfecting holiness". We were made holy when we were washed in the blood of the Lamb. His Blood cleansed us of sin, our slates were wiped clean by the Sacrifice of the Cross. But, that just began the process of holiness. God provided the means for us to be taught how to "perfect holiness":
1) The Bible teaches us time and time again and in so many ways to
"...put on the new man, which after God is created in righteousness and true holiness." Eph 4:24 Stop right here and go to the BlueLetter Bible and type in "put on". Read those references and see just how the Bible teaches us to "perfect holiness".
2) The Holy Spirit was given to us mainly to us into all truth.
Jhn 16:13 Sometimes I think we forget that. Or we don't trust the leadership of the Holy Spirit. But, the Holy Ghost wasn't just given to us to speak in tongues or use the gifts of the Spirit. His purpose is to lead us into ALL truth. That leadership denotes the process of "perfecting holiness".
3). The Lord has provided us with the 5 fold ministry for the pupose of helping us to "perfect holiness"
Eph 4:12 For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ: See the word again: "PERFECTING"? Holiness is a process that is, I believe, unique to every individual. As we study the Word, obey the Holy Spirit, and follow the teaching of God's Word, we will work toward perfection. Its not for me to decide what "holiness" means for others. I have to "examine myself", "be fully persauaded in my own mind" and "work out my own salvation", which, if I do this correctly, won't leave alot of time to judge the "holiness" in the lives of those around me. Some may ask, then, when do we attain holiness? To that I answer: At the cross. When His blood washed away our sin. Paul suggests that we never quite attain it until our race is over. When we stand before God, then we will have attained "perfection". Phil. 3:12-15.
I will say this: When I judge anothers spirituality, or lack thereof, I slip. The Bible is clear that when I judge another, I violate the principles of God's Word. My own "holiness' is eroded when I judge others. I may not agree with anothers standards. Perhaps he is too strong, or too weak in my opinion, But that is between him and God. I don't have to agree with everything a brother or sister does or does not do. But, I am compelled by the Word of God to agree with my brother or sister spiritually. Of that, I am sure, because, through the Holy Ghost, we are one in Christ.