f.d. means före detta, which translates as former
undt.m. means undantagsman, which is a person who for some reason gets his keep from the people on the main farm. He could be somebody's parent, or he could be a former tenant, for instance.
An åbo was a tenant, and did not own the farm, but he had a stronger right to continue as the tenant, if he behaved and paid taxes and dues as he should. One of his children could also inherit the tenantcy, if all had been well in the previous generation.