Surface Geometry Manipulation

1. Can a surface be extended with the surface "extend" tool without creating a new surface? The option is available within the "cross extend" tool, but not the "extend" tool. I'm getting a lot of sliver surfaces an would like to avoid the further clean-up step.

2. Is there a way to combine two surfaces into one? The "unsplit" tool seems to work on shared edges on a single surface that's been split, but not shared edges that were created when two surfaces were joined.

3. Can the extend tool pull surfaces in directions other than parallel and normal to the surface plane?

Thank you!

-Mandy