Can interest from masjid a/c be used for baitul mal, toilets, taxes, legal matters, and zakat/fitr?

we have masjid a/c in one bank and baitul mal a/c is another bank. in masjid a/c we have shops deposit amoutn and masjid income like (monthly subscriptions and shops rents) every 6 months we get interest. so we transfer the interest amoutn to baitul mal a/c. my question is can we transfer interest amoutn to baitul mal a/c or can we construct toilets in majsid premiss or can we paid interest amount to municipal property tax for shops. or can we use this interest amount for legal matters. my another question is Baitul mal is a halal amoutn like (Zakat and Fitr) can we mix the interest amoutn in that. because if we move the interest amoutn in to baitul mal a/c again after 6 month we get interest on (baitul mal a/c ). is it permissible ? if not can we create a fresh a/c in that only interest amout we deposit and we use needy people according to the situation. one more questions is Where do we use this interest amoutn can u please mail briefly so that we can follow inshallah.