I don’t know about wrestling, but track and XC are no-cut at many schools. There are limited competition spots for indoor/winter track, but everyone usually gets to compete in dual meets for XC and outdoor/spring track.

They have a website check there. If you don't know the Coach, contact school's Athletic Director

Its very school specific and if the team has cuts or not and what he's good at. You need to reach out to the coaches.

DS is a good but not great athlete so I could see him getting cut from his sport for varsity. Are there any sports he could pick up as a junior? Would cross country, track/field and wrestling still be available for him to try as a junior if he hadn't before?
Do they have jv and varsity levels for these sports ?