While you are right to be vigilant, from the safety of my keyboard, I don't think you are seeing dangerous over-pressure signs (so long as the ejector mark isn't coupled with stiff bolt, loose pockets, etc.)
The WSM series are fat cases, based on the 404Jeffrey. The large internal diameter will have an influence on bolt-thrust, so you might expect to see ejector marks at lower pressure than more conventional designs. I know my 7WSM does compared to some of my other cartridges. This is a complex area (lots of factors) and I'm speculating! I'm not suggesting you should ignore ejector mark/swipe. Probably worth checking your chamber is oil-free and cases have no residual lube on the sides.
Federal primers are quite "soft" and flow more than others. Your cratering isn't accompanied by flattening (look at the junction between edge of primer and head.) If you change primers, drop your load and work up again.
As others have said (and I think you have done), check your jam/jump using the ogive, not over all length. If you are close to the rifling, be careful your next loading is the same, or you may raise pressure by jamming (or reducing available case volume, if shorter.)
No need to chase velocity unless you have a specific application that requires it (e.g. bullet must stay above transonic zone at a given range). Also, being below book velocity is not an indication your pressures are ok.
While it is important to check cases for incipient case-head separation, this is a late sign (unless you have a headspace problem and/or are working your brass too hard with respect to shoulder bump...) The "bright line" can be very subtle and sometimes witness-marks from the FL resizing die can worry you if you haven't seen it before. Probing the inside of the case for the dip/dimple, is also something of a "feel". I have kept some cases that exhibit these features, to show novice reloaders what they are looking for.
If you think you will get better (useable) accuracy at a faster node, or you are chasing a specific minimum velocity, you are probably ok to increase in appropriately small increments. Beware changes in climatic conditions and components between range sessions and reloading respectively.
Not sure what barrel-life a 270WSM delivers at max loads... Don't mess around too much on load dev!