1. Yes-Almost every municipality will require a permit to add a 2nd kitchen. This permit application is also likely to alert them to the fact you are trying to turn a SFH into a multifamily home, which they will not allow unless you are zoned appropriately for it and you would likely need to make the basement an attached ADU (most places the owner has to live on-site in either the ADU or the rest of the house, not always though) or duplex which requires a lot more permits, time and money than just adding a kitchen.
Of course, you could just add the kitchen without a permit. You do take a risk of being reported (unhappy tenant, neighbor) to the city and the city can have quite a bit of leeway to intervene (fines, make you tear out your new kitchen, etc.). You can get fancy with your lease wording and go with no stove (hot plate/induction top only) to try to improve your odds but you still can get screwed over. The right thing to do is get the proper permits-both for your own protection and protection for your tenants (fire code, egress windows).
2. You should get a structural engineer for egress windows (usually required for the permit) and for doing anything with a load bearing wall. Or if you think you have structural issues. If you are just cutting a hole for a vent-no engineer needed.
3. Go to your city's zoning and permit department website to read up on your local requirements. Get familiar with it. Call them and ask questions. You can decide if you want to give them your name and address or not ("calling for a friend" method) Permit process varies city to city. Time depends on the scope of work. Weeks to months is typical, but it depends.