I found the update that mentions the speed reduction to everything except "Top" equipment getting -0.1 to speed. I probably missed this update or didn't read over the notes then.
"-*fixed, Lona default move speed to 4.3, and each mid,bot,midext dress part now -0.1 moveSpeed.(nude move speed bouns)"
Her base speed got buffed so a full set of clothing, ignoring any Top, would put her back to a speed of 4.
If I'm looking at the stats again now with the description, outdated out not, and the nerf in mind:
Top has the +0.05 speed bonus like the description claims and doesn't have a nerf cause it's a Top; this makes sense for both.
Mid has -0.05 rather than -0.1; maybe this is still considered the speed bonus since it's not the full nerf, still a little weird.
Bottom has a +0.1 speed bonus rather than a -0.1 speed nerf; this is still a bit odd, no speed reduction at all.
MidExt has the +0.05 speed bonus and the -0.1 speed nerf; this one is redundant and should just be changed to one attribute of -0.05 to be cleaner code and would match Mid's stat if the speed bonus is still being taken into account
Total bonus of +0.05 is definitely better than other armors with -0.3 due to nerfs, I guess.
So other than the Bottom being only a bonus and lacking any sort of reduction which conflicts with the update and MidExt's weird unnecessary double stat maybe the set is working properly; just coding wise the set looks a bit messy and weird compared to the description, especially since I didn't know about that update.