Tax treatment for duplex selling

[Yoshi Uem]

Hello, 

I live in one unit of duplex and rent the other for more than 2 years of last 5 years. Now I am thinking of selling it. Can anyone verify the tax treatment as of today that a gain from owner occupant unit is applicable for Sec 121 exclusion, and a gain from rental unit is applicable for 1031 exchange?

If so, is the gain simply divided to 50:50 between 2 units? My duplex units are almost identical.

Also, after sold, my understanding is that, I can purchase only non owner occupant property via 1031 exchange, but I can purchase either owner or non owner occupant property via Sec 121 exclusion. Is that right?

Thanks for your time!

Yoshi