Several points here.

1) The fork & seat post look more like cuts/gouge than cracks.

2) Loosening torque and tightening torque are different. Especially on parts that have been together for a long-time. Consider Loc-tite on a bolt, then tighten to 5Nm. It's going to take A LOT more than 5 Nm to get it to come out. Sweat, gunk and corrosion can all act like Loctite. Just because it was difficult to remove doesn't mean than anything was improperly torqued.

3) The stem is the most suspect looking, but that's easily replaced. The question is how likely are the inserts to pull out.