Is it permissible to use haram interest and profits from employment compensations and savings in a usurious bank to pay off a housing loan that involves haram from the same bank, in order to be rid of the haram in both instances?

Working in a Riba-based bank is forbidden because it falls under the category of cooperating in sin. The salary and end-of-service gratuity resulting from it are ill-gotten wealth (mal khabith) that is not owned by the employee or the bank. It should be spent on general Muslim welfare, such as orphanages and for the poor. It should not be spent on the personal needs of the one who acquired this forbidden wealth, unless that person is poor and in need, in which case it is permissible for them to spend from it only to the extent of their need, such as to pay off a debt.