1. My favorite vintage Lambda is the Nova Classic due to its warmth and smoothness relative to a lot of the other Lambdas. That being the case, would I likely prefer the 007mk2 tonality over the 009?
You might even prefer your Lambda over the 009... but you won't get the same bass extension, clarity, resolving power, tonal correctness.
Warmth and smoothness is achievable with the 009 as well, give it a good amp and source. Some treble hash and a bit of technical-feeling (less soul), but quite fine.
I prefer the the latest 007 over the latest 009, but I think the 009 are more universal, will appeal to more people as it sounds more open.
2. Is the 007mk2 lower, but in the same general tier, as the 009 in terms of imaging and detail retrieval, or is the 009 much superior in these areas?
Musical details are more apparent with the 009, partly since the big difference in FR in the 2-6 kHz domain, partly because of the difference in sensitivity and membrane thickness, too. I think both bass and mids are better resolving with the 009. However, the 007 may sound more coherent, but it's also because it's more forgiving to source equipment. Most source equipment today have a harshness, hardness or a technical sound profile, though in later years good advances happened.
3. Will a 353X drive the 007mk2 "sufficiently" (not optimally, but sufficiently) or would that be a complete bust?
Yes, it will drive it, even the 007 Mk1. A BHSE will not make it louder, but more complete, smoother and deeper. A Phenomenon amp is like a dynamic and spatial boost-bust in comparison (Mjölnir Carbon is a distant uncle).
Basically I'm leaning towards a 007mk2 but if there is a distinct gap in technical performance between it and the 009 then I may go 009 instead despite some qualms about the tonality. Another factor is that by most accounts the 009 should be a better fit to drive with a 353X which is all I'll have on hand, other than an SRM-1/mk2 and a 252S which won't help much. I do plan to upgrade amp but not until I decide whether to get an actual amp or an iFi Iesl.
If you are thinking in the context of the 353X or iFi, maybe better get a T1 with mods. But check out the value kings linked above, e.g.
high-amp or
Konka, or second hand Mjölnir stuff.
Overall, I think the 009 is safer bet for long term, especially now that the 009S and X9K are around as well. If you want slightly warmer sound to the 009, try the
pad mod.
The same mod is doable for the 007, it opens up the sound a bit, actually it's even more suitable for the 007 than for the 009. Then, the 009 pads used on the 007 are another "mod", as they sound best on the 007 as well. Also, taking out the spring from the 007 ear pads (and eventually doing the pad mod) opens up the sound, bringing it up in resolving power as well. The port mod is another thing you can do. A lot of room to play with the 007.
Note that you should NOT listen critically to the 007 until it's adjusted properly to your head shape. For both the 007 Mk1 and Mk2, I needed to shape the headband to be flatter, i.e. provide more distance between the top of the drivers, and follow my head shape from there down, with a borderline lose fit, when bass is not diffuse yet, but it has most impact, depth and sound stage is biggest. I ended up the two headbands with slightly different shape, so that they track my head front to back as well. Your head may require different setting, but IMHO this kind of optimization is a must with any 007. I really liked the 007 headbands (less so for the ringing), as they allowed nice fine-tuning of the fit.
The 009 is not so sensitive about it, and its headband is not even adjustable for shape (only for size), unfortunately.
