Obi110 with one analog phone line and one sip phone with voicemail?

[Jabrwock]

Here's my proposed setup:

incoming phone line goes to LINE in Obi110 connected to a raspberry pi running pbx (raspbx or freepbx).

I want the Obi110 to route to the pbx, directing incoming calls to 1 of 2 extensions.

Obi110 is attached to LINE IN, plus an analog phone, and an ethernet switch connecting it to PBX and Obi100. This is a local-only network.

Obi100 is attached to another analog phone, and to the switch.

Extension 1 rings on analog line all the time.

Extension 2 will ring the analog line only on Monday nights, and the Obi100 (and its attached phone) all the time. PBX will provide voicemail and send MWI (voicemail indicator) to Obi100.

Is this doable?