I did the same exercise a few years ago and, in the end, decided to go the route of multiple tents instead of the one-size-fits-all solution. My decision was based mostly on the fact that when I'm hiking with my dog, I have to carry everything, while a second person means splitting up the load. Also found that the multi-tent cost wasn't necessarily more expensive.
When I hike with my dog, I take a Contrail. Small footprint, bug protection, easy tent to use and fits us both comfortably. Picked up a used (but in super condition) Contrail for about $100.
About the only time I share a tent is when my son hikes with me. I got a Squall and we really like this tent. Picked it up used for $100 as well. The two of us hike in the GC often, so I splurged last year on a cuben Trailstar. Great for the two us but light enought for solo or solo+dog in no-bug conditions.
Now, if the used Contrail and Squall hadn't been available, I was planning to buy a cuben Lightheart SoLong 6. Big enough for two, bug protection, great ventilation (I have a Lightheart Solo), light enough to carry solo. I think it would be a palace for hiking with a dog. A little pricy but there's a 20% sale going on...