(18) To invest any funds not needed for immediate use or disbursement, including any funds held in reserve, in obligations issued or guaranteed by the United States of America or the state of Connecticut and in other obligations which are legal investments for savings banks in this state and in time deposits or certificates of deposit or other similar banking arrangements secured in such manner as the authority determines;
(19) To procure insurance against any loss in connection with its property and other assets, including mortgages and mortgage loans, in such amounts and from such insurers as it deems desirable;
(20) To the extent permitted under its contract with the holders of bonds, bond anticipation notes and other obligations of the authority, to consent to any modification with respect to rate of interest, time and payment of any installment of principal or interest, security or any other term of any mortgage, mortgage loan, mortgage loan commitment, contract or agreement of any kind to which the authority is a party;
(21) To the extent permitted under its contract with the holders of bonds, bond anticipation notes and other obligations, to enter into contracts with any mortgagor containing provisions enabling such mortgagor to reduce the rental or carrying charges to families of persons unable to pay the regular schedule of charges where, by reason of other income or payment from any department, agency or instrumentality of the United States or this state, such reductions can be made without jeopardizing the economic stability of housing being financed;