There is a way that enables clicking through buffs and debuffs with a change to the source code if you're still interested. It looks like there is provision to disable tooltips which would also allow this but for some reason in the classic version it is removed.
Find the LunaUnitFrames folder in your addons and open up the modules\auras.lua file in a text editor. Find the Auras:OnEnable(frame) function.
Code:
After this line:
local button = CreateFrame("Button", frame:GetName().."BuffFrame"..i, frame.auras.buffbuttons)
Add this:
button:EnableMouse(false)
Comment out these 2 lines below it with the hyphens:
--button:SetScript("OnEnter", showTooltip)
--button:SetScript("OnLeave", hideTooltip)
After this line:
local button = CreateFrame("Button", frame:GetName().."DebuffFrame"..i, frame.auras.debuffbuttons)
Add this:
button:EnableMouse(false)
Comment out these 2 lines below it with the hyphens:
--button:SetScript("OnEnter", showTooltip)
--button:SetScript("OnLeave", hideTooltip)
Save the file and reload.
Not an official edit but it does work, you lose tooltips but at least you can now click on the whole unit frame.