Would these be reasons to modify?

Custodial parent has unpredictable schedule and elementary age kids are left at the house alone, but neighbors check on them occasionally.

CP does not enforce homework or study, all kids have failing grades in 2 or more areas.

CP has had 7+ live in girlfriends in less than 3 years, and such frequent changes to who is and is not part of the kids lives is very stressful for them…some I can prove have criminal records due to drug abuse and distriburion and breaking and entering.

CP often makes last minute changes to plans so kids are with the non-CP so the CP can go out with friends or bar hopping.

CP has not attended any school conferences in over a year.

CP has not attended or taken the kids to any of their school and psychologist recommended therapy appointments to help with anxiety and coping skills…I take them.

CP has not taken the children to the doctor for over 2 years, not even to update immunizations, yet refuses to let me have a copy so I can take them and get everything up to date.

Since original order CP has gone from having kids 5 nights per week, to either 2 or 3 nights per week. And has times when he does not contact me, to let me know what to do for the kids.

CP does not provide any of the kids school supplies or shoes…his aunt sends clothes a few times a year, but otherwise is all supplied by me.

CP has recently objected to oldest child attending on campus tutoring at school free of charge because he claimsnit to be a waste of time, oldest child failed last year and was retained, and now CP claims tutoring as a waste of time because oldest cannot be retained again.

CP does not give enough notice on taking kids out of state when he does. Telling me less than an hour ahead of time that he is taking them 300+ miles away, unless its an emergency and changes plans that were previously set.

CP, according to the kids, sometimes lets the women he has stay there yell at and call the kids derogatory names and according to them, threaten them physically, as well as lock the cabinets so they cant have snacks.

CP continuously refuses me any access or copies of the kids medical records, social security numbers, birth certificates, and other important information as was part of our agreement.

How much, if any of the above stated could I use to request a modification of custody?

I would like to thank you for the efforts you have made in writing this post. your provided information is easy to understand and implement.

It sounds like a number of the items that you have listed would constitute a substantial change in circumstances warranting a modification of child custody.

Which of the above listed reasons, if any, would you recommend I put my focus on should it take court to get a modification?

You should address all of the changes and focus on the changes that adversely impact the children.