Warning: Windy post....
Back when I was wiring homes and light commercial properties for a living 34 years, I adopted some basic rules for my wiring methods. I would try to keep the wiring of my circuits simple...so that the future possibility of adding loads, fixtures and even trouble shooting of my wiring ....would be made simpler for me or for someone else...
I would do service work also. Some of my service calls such as in finding the reason for flickering lights, randomly functioning or dead receptacles etc...would have me tracing a circuit that would start in one bedroom, go through halls, up in to the attic, back down to a basement light.....
To me, it was really strange workmanship for the electrician to adopt this kind of wiring methodology. .. It is so simple to start at the breaker box with the home run cable, then just daisy chain the loads in the same proximity say, picking up bedroom one and two... Living room and main hall, etc..
And another reason for my simplistic wiring methods, the required and practical task of having to label all breakers as to what loads they control on the breaker box directory sheet. With the circuits loads ran all over the place like they were shot from a cannon... wow, it is tough writing all that info down on that little line provided on the breaker box door...
So to your specific question about option #2, I see no reason to go up in the attic and tie on to an attic fan circuit, while possibly putting the fan/night on two separate circuits. When a person is troubleshooting circuits in a residential property, I feel that most residential electrician's are surprised to find outlet boxes fed by two separate circuits. ....
Personally, I never liked putting two feeds in one box unless say, it was in a commercial /garage or large workshop where I would have to gang two receptacles in a two gang box that required dedicated 20 amp feeds. ...
When I was a hospital electrician, finding two separate circuit feeds in a box was not surprising, of course. Commercial /industrial wiring applications are like day and night...when compared to dwellings. In those buildings also, it was common practice that whenever a box had more than one feed source to it, it was labeled as such to warn the service person that just killing one breaker...would not kill the power to the whole box. .
To sum up my novel here, whenever one has the opportunity to do the wiring in keeping with good wiring practices...by simply keeping the fan/ night light on the same circuit like you can do...the above is why I picked #1 option. Good luck on your project and work safe ! . JMO
