LR3 Getting Started questions

Question

I've been using Aperture since v2 and am looking to move to LR 3, but have some functionality questions before purchasing LR.
Right off, this isn't meant as Aperture can, LR can't post.  It's meant as, LR has features that I like and am considering switching to it over Aperture as a result, but the following are 'must-have' and I just want to know from a technical standpoint if I can accomplish the same (similar) workflow in LR3.
1.  Keywords: Can I assign keywords via the keyboard?
Aperture
Keyword set: Me, You, someone else
Opt-1 will assign 'Me' to selected image(s), Opt-2 will assign 'You' to selected image(s).
Keyword set: Cat, Dog, Rabbit
Opt-1 will now assign 'Cat' to an image, Opt-2 will assign 'Dog' to an image.
Can the same concept be done in LR?  If so, a link to a tutorial would be appreciated.
2. Smart Albums (Collections in LR)
Aperture
I have a Project with 100 images, in that project I have 30 images in an Album1, 50 images in Album2.  Using Smart Album, I can create a rule that shows me only the 20 images that aren't in any Albums (ie. Album1 or Album2)
Can the same concept be done in LR?  If so, a link to a tutorial would be appreciated.
3. Refenced vs Managed
I have a Reference library in A3.  Files reside on external HDD (~100 GB), library (previews, keywords, etc...) resides on internal HDD (~20 GB)
Reason, I only have a 120 GB internal HDD.  Managed wouldn't fit on my internal HDD.
I've added three images to a test LR, 2 MB each, and the resulting LR Catalog folder in the Finder is ~3MB.  Is the normal overhead in LR, ~50%.  If so, that won't work for me.  Are there pre-sets to reduce file info in LR?  Meaning, low-res previews, etc...
4. Drag-Drop from Finder
Is there a way to drag-drop images from the Finder to an existing Catalog?

Answer 1

1.  Keywords: Can I assign keywords via the keyboard?
Same as Aperture.
Alt/Opt+n to assign keyword-n (where n is a number from 1 to 9);
Alt/Opt+0 (zero) to cycle through Keyword Sets.
2. Smart Albums (Collections in LR)
Create a Smart Collection with the following rule: Collection doesn't contain "Album1" AND Collection doesn't contain "Album2".
3. Refenced vs Managed
Lightroom doesn't have "managed", only "referenced".
The catalog size grows mostly because of the preview cache, which is always located next to catalog (unless you use some hacks). In Catalog Prefs, you have options for preview quality (low, med, high), size (1024, 1440, 1680, 2048 on the long side) as well as the max. time before discarding 1:1 previews.
Those 3MB is you catalog + preview cache, and probably some initial overhead for an empty catalog (an empty database cannot be as small as 0KB).
As a general rule of thumb, I think 1MB per image for the preview cache is a good guess. So, for a 50k catalog you need 50GB for preview cache. The catalog itself must be below 1GB for this number of images.
4. Drag-Drop from Finder
At least on Windows, it works quite well. You drop the files and Lightroom pops up the Import dialog with only those files that you've dropped being selected for import, even if the folder in Finder/Explorer has more files.