Hi David
Just on a big catch up round!
Mouth ... My initial thought was the same and was going to shoot the Mouth of the Grand Union Canal into the Thames at Brentford (as its directly behind where I work) but it wasn't very inspiring other than the Thames Lock.
Like your shot, I think that Blue of the bridge is a nice Colour anchor against the rest of the shot, Nice light on the wall and muddy bottom! Always makes me wonder what's down in all that mud! bet theres stuff down there that could tell some stories!!
Crowd ... Love this shot, Really impressed with it especially as it was hand held too! Think its level if you look at the verticals... Well shot Fits the theme well, Nice bright colours too, I like this

.
Close Up ... Nice close up shot there. I think the lighting is great. Nice spotlight right on the button ... I mean zip! Just looked at the SOOC and that excellent work using a torch for the lighting. Square crop with spot on DOF looks great to me.
Machine ... Cracking Lovely great big armature, and nice commutator ring fair bit of copper there!! It always amazes me how they made those large machines back then, I guess the tolerances weren't that critical! Great lighting in this shot very subtle

Bit of a Beast of a tractor then... The Russians like there big odd machines don't they, looks like some serious power being used there! Like both the shots I think I like No1 best (just as its electrically related) Lighting in both is nice. Good Stuff.
Alphabet ... Great interpretation! cant believe I use a keyboard all day and couldn't think of any thing alphabet related

Fits the theme well, cant decide which version I like best, Green or not so green that is the question? Think its Green, highlights the letters well against the subtle background and lighting.
Sound ... I think that was a apt test for your lens

That's when you can tell how good your Lens and Camera is! that was a fair old crop then... I think you have done a great job of processing the shot, looks like he is serenading someone on a balcony. Works well.
Sound Remote ... TP52 makes you do things you would not have necessarily done before.... Like clean the remote

. Clear, simple, sharp and works.
I think the musician takes it here though...
Nice work David
Nice lighting and tastefully done! Good Work!