[Jeff Hinkle]

From Adobe Help:

In a sequence, select the clips you want in the composition.
Right-click any of the selected clips.
Select Replace With After Effects Composition.

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Like Joseph said, that kind of shortcut assignment is handled in the mouse software, not After Effects. You can usually (depending on the mouse) specify which application will treat “1” as “undo.” So, for example, you could set “1” to be “undo” in AE and be “brush tool” in Photoshop, if you were so inclined.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

I guess that depends on exactly what you’re expecting by “clean.” How are your strokes not-clean? Most of the brush presets in Photoshop should give you decently smooth lines with no tweaking. Can you post a screen shot of the result you’re getting that you’re not happy with?

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Try this: Open your original (not the save-for-web result) and check View>Pixel Aspect Ratio and make sure it’s set to Square. If you’re working in a non-square environment with Pixel Aspect Ratio Correction enabled, your images will LOOK correct in Photoshop, but not when you save them out.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

You could just adjust the opacity of your Layer 4 (with the gray shape) and then render the project with an alpha. Won’t give identical results to Multiply, but close enough.

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Multiply isn’t an alpha effect. It’s a blending mode, meaning it combines the values of the pixels of its layer with the layer below it. No layer below it? No blending. So outputting it and dropping it over a source in another program won’t work like it will internally in After Effects.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

If I’m understanding correctly what you want to do:

Draw your path.

Select your Brush tool.

Set the brush the way you want it (size/shape/color).

In the Path palette, select the path and click the Stroke Path with Brush button at the bottom (the hollow circle).

That should stroke your path with the selected brush.

If you have Illustrator, you can do basically the same thing but with a lot more flexibility, especially if you want to go back and edit the path or brush later.

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

You can simply drag the masked layer into the second document (which I like for added flexibility of keeping the mask for possible refinement), or, if you really want to copy/paste, make a selection of the mask (on Windows, I think that’s ctl-click on the mask thumbnail in the Layers palette), then copy, switch to second document, paste.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Questions of legitimacy aside, in answer to your second question, it’s almost always better to learn how to do something the “hard” way before looking for an automated solution. That way you know WHY things happen and can control them instead of trusting to an external source and hoping for the best. The whole “teach a man to fish” theory.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Couple things:

1. Who is doing the resize on the image, you or YouTube? Are you providing the image at the exact size YouTube requires? You’ll have a lot more control if you provide the final size rather than letting their system do it.

2. Your thin diagonal line pattern, when reduced, is going to smear together and essentially “gray out” all your colors. That’s why everything looks washed out. Try turning off the lines and see what happens to your colors.

—
It is easier to destroy than to create.
More fun, too.