OOhh I really like that cabinet style and color. I'm supposed to be looking at something else, aren't I? O yeah, the hood. It really looks like a lot of space to me. I wouldn't worry about it at all (unless it just happens to be at an eye-poking height for someone). If you're doing gas, it'll be a tiny bit less because the burner grates usually bring it up a little over where an electric would be but even so I think it's a very generous-looking gap. If anything, I think it might end up looking BETTER lower. I really really think you're good here, unless you had a 30" tall backsplash mural or something! By the way, I really like your cabinets. Are you going without handles on them?

I am the resident expert only because real HVAC systems engineers don't frequent this forum, as far as I know. Noise introduced into the kitchen will be significantly reduced if an external blower with silencer can be fitted. A lot of the high frequency blade tip turbulence caused noise will be removed. This is also true of an in-line (duct mounted) blower. The issue of the neighbor is difficult to assess. What is the configuration of his or her windows relative to your potential external blower (1500 CFM I assume you meant). Your own window sound transmission is also an unknown. Generally, the external noise could be abated by (a) using a silencer on each side of a duct mounted in-line blower, or (b), using a deliberately under-driven* "up-blast" commercial blower (mounted as a side blast). (I think opaone is using an under-driven blower for his new system.) It is also possible to use a chase to move the blower up to roof level. I have a 1500 CFM nominal Wolf (Broan) blower on my roof. Its sound level is detectable but not obtrusive from the ground, but it might be if in a wall location where the sound is "trapped" between two houses. Possibly a more expensive but similar in design Abbaka downslope unit would be marginally quieter. ------ * commercial blowers of this type can use a pulley system between motor and fan that allows for different ratios. By choosing a ratio that operates the fan blades below their rated speed when the motor is receiving maximum voltage, significant turbulence noise can be avoided. The physical cost is a larger unit than would otherwise be required for the desired flow rate. Residential blower fans are directly coupled to their motors.

I had a 6" height restriction and venting issues as well as requirement of twin fans for a 1000 cfm. Imperial hoods (manufactured in California) met all of those criteria plus additional custom features. I suggest you call the the manufacturer direct with your questions. The office folks know a great deal but will send you to their engineer if stumped. You might also try the appliance forum for assistance.

The last image appears to be of an external blower housing in a wall mount. Perhaps it is a blower housing without a blower. You might want to check just what is in the guts behind the "wood top" and what you can see in the blower housing. The baffles should be removable for cleaning. If you don't intend to use the range for serious cooking, the existing hood might be sufficient, particularly as it seems you don't have a deliberate means of make-up air. By serious I mean with hot oil or grease at vaporization temperatures. Normally, I would recommend the following: A replacement hood should include baffles across most of the entire width and depth of the hood. In this case that would be most of 30 x 19 inches. Call the space 2.5 x 1.5 ft, or 3.75 sq. ft. At 90 CFM per sq. ft., the flow needs to reach ~340 CFM. This would call for a 500 CFM rated blower. In many municipalities, this would also require addition of a deliberate MUA system, which might mean only a duct with damper and filter, depending on any combustion appliances, what type they are, and whether they have their own MUA. I am unclear from your description whether you live in such a temperate area such that screens always allow air passage. A replacement hood should probably be at least 22 inches deep, and have lights. Nonetheless, a larger hood, which can be higher, but with commensurate additional CFM, will better capture and contain cooking plume effluent. For general types of hoods and sizes Wolf sells, see the Wolf Design Guide. Touring Broan's website might help. A mind boggling number of choices may be found at AJMadison's site.