You are absolutely right and I think McNeil is going to try to throw in reasonable doubt about who really was the one that killed Maria. Laurean has already admitted that he buried her there.
If LE found no forensic evidence on the crowbar and it may have been cleaned before handing it back to the friend, then I expect that they will have a high powered expert on the defense's side that will come in and state in their opinion the fracture to Maria's head were done after she had died and was due to the heat. Also the ME could not say with certainty that the slash to Maria's throat was done after death so, imoo, McNeil will have an expert say it happened before Maria died to tie in with the suicide theory.
I just don't visualize her as a battered woman. The Marine Corps was everything to Laurean. The Marine Corps is coming down hard on those who commit domestic violence and imo, Laurean would not want any blemish on his record. Before this happened he was an outstanding Marine who had already been meritoriously promoted.
So for me that leaves two options when it comes to Christina. She is really that dumb, naive and not a very observant person even in her own home and truly believes his *advertiser censored* and bull story from beginning to end.
Or she stays with him because she knows too much and perhaps participated in the crime and it is much better to stay married and protected by marital privilege where it protects them both from incrimination.
imo