A few questions, new SM setup

[Senact]

Hi, I am new to the board, I posted in the introductory forum if interested.

I had a few questions for Stepmania experts out there. I am trying to build a solid Stepmania experience for at home. I don't have any pads atm, but am looking to purchase a couple of the Impulse Pads when they release later this year. I almost bought a set of Precision pads, but after reading more about them, the Impulse pads sound very promising and worth the wait.

Currently I have SM5 installed and have been keyboarding to practice my arrow reading skills. (The FFR game on this site looks pretty neat, so I'll be checking that out too). I much prefer to play on a pad, but as that is a 6 month wait, I will be keyboarding until then.

I've been researching Stepmania but find the available resources somewhat confusing, which leads me to a slew of questions.
- Which is the best version of SM to run with that has the most support?
- It seems content for say... 3.9 doesn't work with 5.0, is that true?
- Theme packs are the overall look of the game menus/sound effects and announcers is just the voice work correct? Are there any other customisation's worth looking into?
- On arcade and home versions of DDR, there was animations on the screen while you played (usually a dancing person). Are there any custom animations available for SM or just a static image/black screen?
- I currently have all the DDR mixes and ITG 1-3. My pad skills are likely reduced to playing red 7 foot songs (I still call them feet, but that might be a DDR thing). Are there any other packs recommended for people playing in that 7-10 foot range? I don't see myself ever playing songs 12feet+, that just looks so crazy. Even on keyboard I can barely pass 9foot songs as I can't follow the arrows fast enough yet.
- There seems to be a lot of packs that only have one difficulty which is usually a blue 11+ footer, I assume there are no versions of this song with easier step patterns unless I made my own? There are so many good songs I'd love to play but are just way too difficult.

In fear of going on way too long, I'll stop the post here. Thanks in advance for any help you can provide!!