I'm in agreement with the other responses here that the structural issue should be your main concern.
I try to advise my buyer clients to purchase a house with "good bones".
Keep in mind that it could be a real concern to future buyers when it comes to reselling the property even if the foundation problem is addressed now. Buyers become wary when they observe work that has been performed to solidify foundation issues.
Prudential Connecticut Realty
Most buyers tend to overlook cosmetic cracks and the foundation settling. They are often considered part of the aging process but when this activity crosses over to becoming a serious structural concern, second thought and further evaluation is most often the best course of action.
Of additional concern should be the condition of the home's "big ticket" items. HVAC, the roof, wood destroying organisms, kitchen & bath condition, etc.
The "red flags" you have already identified should prompt you to proceed with great caution making certain this one doesn't rival a "money pit."
Licensed Associate Broker
Accredited Buyer Representative
GREEN Designated Agent
William Raveis Legends Realty Group
You should definitely have a structural engineer evaluate the property. The home has obviously settled over time and this is a direct result of the soils beneath the home. Typically the reccomendation will require helical pins or piers to be installed that will jack the house back up to a more level condition and stabilize it. Once these piers are installed that section of the house will not move again. There is usually a lifetime warranty that would come from the installer. The rest of the items you listed are all relatively minor though there's nothng wrong with having your agent try to get some consideration from the Seller, but the thing to focus on is the structual work that the engineer determines needs to be done.
All the other stuff is minor. The big item is the structural integrity of the home.
Also, if there are documented structural problems, Homeowners insurance may be a problem to get and or payout.
Best of Luck to you.