What's interesting is that unbraced tops do vibrate in very similar patterns to braced ones. You could make a solid spruce top thick enough to take the load of the strings, but it would be too heavy to sound well. Bracing is there to add stiffness without adding too much mass.
Bracing a top 'wrong' can really kill the sound. Makers have devised, by trial and error, several bracing patterns that work well to produce sounds that people like. Even using one of these 'standard' patterns won't guarantee a good sounding instrument, particularly if you make the bracing too heavy. That's what techniques such as 'tap tone' tuning try to do; to figure out where to remove material from braces to make the top work well. Chladni patters are just a 'tech' way to make tap tones visible, and home in more precisely on the pitches. It seems to some of us that the shapes of the patterns are more important than the pitches. The pitch of a resonance tells you something about the ratio of stiffness to mass, and that's helpful, but in the case of a guitar the absolute stiffness is more important than the ratio. A very low density top could end up quite light and still have a resonant pitch in the 'right' range, but could fail to have the requisite stiffness.
Frederich's 'sandwich' top is, in a sense, another approach to the problem. The top itself is a sort of 'extended I-beam' which derives it's stiffness from thickness, and eliminates most of the wood in between by replacing it with a light weight honeycomb material. If the layup is made thick enough there will be little or no need for other bracing, with the possible exception of an upper transverse brace to take up the bridge torque. This is critically dependent on good and long-lasting glue joints between the top and the honeycomb. It's easy enough to fix a bad joint once you know where it is, but hard to find it,if the experiments I've done are any indication. Time will tell.
The other main 'modern' design that does much the same thing is the Smallman 'lattice'. A balsa/CF I-beam lattice takes the loads, and veneer thickness top is simply a membrane across the structure to move air and produce sound.
In both the 'sandwich' and 'lattice' tops mass has been significantly reduced without losing the needed stiffness. This tends to shift the modes of the completed guitar upward in pitch, which gives a different timbre to the sound from the traditional top. Some folks don't like it, others do. There are other methods being tried (such as Gore's 'falcate' bracing) to accomplish similar ends. Moving the other way, into more 'traditional' methods of construction, some makers have used carved arched tops and back to gain surface area to produce sound without increasing mass out of proportion. Again, time, and the market, will sort it all out eventually.
To get back to the OP: those are reasonably good looking modes. Your mode at 270 Hz (?) looks like the 'ring+' mode, which is one I tend to concentrate on. What bracing system are you using? In general, what I've found is that the more 'good looking' (that is, well defined and reasonably symmetric) modes I can get on a top, the better the guitar tends to sound. One thing I wish I could get more people to do is to explore the modes of a simpler system first, to get an understanding of what the modes you see really are. If you can get a square (or several!) of expanded polystyrene bead board (not the more homogeneous rolled insulating board) it's a good thing to experiment with. Expanded bead board has the same Young's modulus in both directions, where most materials have a 'grain' introduced by the way they're made that makes them stiffer in one direction than the other. Glass is another material that is 'isotropic' like that, but it's harder to work and harder to find the modes on. Bead board is easy (but messy!) to cut up, and you can explore different shapes. Most of the lower order modes on a guitar top are versions of what you'll see on a square plate of bead board, and you can add masses and/or stiffness elements easily to see what effect things have without messing up an expensive piece of spruce.