They will never know (mostly): Sorry mates, my picture host does not allow viewing of pictures in Oz. PM me & I'll send ya a copy. Apologies. You're not missing much anyways.
I am stealing from HO too, but in the other direction for my Sn42 (1:64 scale on 16.5 mm HO track) layout. I am using cheap HO track and locos to bash into various S scale critters. HO couplers work for S as they are a bit overscale anyways. OO (1:76) Euro style fixed axle wagons pass for S scale mining ore carts. HO windows work fine for S, they are just smaller, the same is true for using them in N too (in some cases), they would just be large windows. Doors are a different story though, you pretty much have to use the correct scale, with the exception perhaps of warehouse doors like on your warehouse here. Had you not told me that this warehouse you have pictured was HO on an N scale layout, I would never had known. If it looks right, use it!
It looks fine from where I sit. Certainly once this scene is finished, nobody would even be able to guess it was a non-N building in origin.
Buildings are usually way bigger than we model them, so an HO one will often work fine in N, it would only be doors which would need altering (if it had any).
Nicely done. HO scale deserves it anyway! And for large, generic industrial buildings like that, the metal siding they use comes in a variety of different shapes and sizes, so it's relatively accurate for N scale even if it is HO.
Champ HO end decals used for sides of N scale Koppers Cresosote tankcar. (I had to draw my own Koppers logo, did it 4 times actual size and color-copy reduced it, in the days before I had Photoshop and color printer) Stealing from 1/700 scale... Japanese harbor crane kit, mft for use with 1/700 waterline battleship models, kitbashed to N scale gravel loader.
ConCor tried once a long time back to have HO/N buildings but it was an inapproptriate choice. But you have to wonder why some of these dual scale companies don't make structures that can be used in either HO or N (or HO and S). Certainly it wou ld give them a larger sales audience without having to crank out two whole different kits. One company I'd like to see do this is one that makes that big power generating station in HO, from Custom Model railroads ... with different door sizes and scribe lines on the wall to cut down the coal unloading bays to N scale car height it could be a nice big N building too.
Nicely done! Recall also that the Walthers HO steel blast furnace and mill have been used for N since they are closer to scale to the real thing. Replace the stairs and handrails and hey presto. The practice of manufacturers condensing real structures into relatively shrimpy HO ones works in our favor. Sure, it brings down the cost and allows people to fit more industries on the layout. But, to my eye, there are a bunch of very large HO layouts out there that look odd with smaller-than-expected industrial structures.