Based on the information provided, an attic mounted antenna may be successful. I have to say maybe, because attics can be built with materials that reflect or absorb RF.
That said, I would try a mid sized UHF/high-VHF antenna. The Winegard HD7694P and Antennacraft HBU-33 or 44 for example.
Aimed at 196° (compass) you will get a fairly full lineup... but PBS and ION will not be stable if you see them at all. I would start with the one antenna and hope that my prediction re. PBS and ION is wrong... there's always a chance.
If you don't see PBS or ION and you 'need' either or both, TinLee.com is still in the business of building filters and antenna combiners. They would be a good source to check with if you are willing to invest in a dedicated antenna for each station.
I'd try using a passive 8-way splitter. You can add a preamp such as the
Antennas Direct CPA-19 or
Winegard HDP-269 or a distribution amplifier such as the
PCT-MA2-M if it proves necessary. When an amplifier is needed, it's best to mount it as close to the antenna as is practical, this offers the best quality signal to the amplifier, providing a correspondingly higher quality signal down-stream.