There is no departure tax if you were in Canada for less than 60 months, but only in regard to assets that you owned at the date you moved to Canada. If you purchased them after, there may be departure tax, depending on the type of asset.
If you had no income for 2023 you dont need to file as your income was pre the date you became a tax resident in Canada. Residency is a grey area though!
Do not use an LLC. The tax effects in Canada for an LLC mean you will likely be double taxed as Canada treats it as a corporation, not a flow through. An LLP should be ok.
Yes, you can file late if you dont owe any taxes. Just beware that if you have to file the T1135 (foreign assets) that cannot be filed late, or there will be severe penalties.