In determining the amount of bonds to be issued, the legislative body may include all of the following:
(a) All costs and expenses and estimated costs and expenses incidental to or connected with the acquisition, construction, improving, or financing of the improvement.
(b) All engineering, inspection, legal, and fiscal agent’s fees, expenses in connection with the formation of the district, costs of the bond election and of the issuance of the bonds, bond reserve funds and working capital, and bond interest estimated to accrue during the construction period and for a period of not to exceed 12 months after completion of construction.