How do you hold title, as tenants in common? As joint tenants? Getting their name off the deed is easy, if they agree to deed the property to you alone. If they don't agree, it's pretty hard, since they have no reason to give up their share of the property, and you may have to file a lawsuit for partition.
Getting a co-owner's co-mortgagor's name off the mortgage is very difficult, since no lender wants to reduce their sources of payment. You could possible re-finance the loan in your name only, which may be doable if your icnome is sufficient.
You're best off hiring a real estate lawyer to review your property records and figure out how to reach your goals under the existing circumstances.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.