My $10 stick blender (Walmart) has lasted forever. I think that's what most people use.  What's nice is that it's save and doesn't incorporate air bubbles.  I think you're much more likely to splatter with a KitchenAid type mixer. 

Perhaps there was something wrong with yours?  I'm not sure. Or you may be mixing too long. I also give mine a break and hand stir now and then. Most of my soap traces within 5 minutes.

That said I've hear people using mixers and even blenders.  I still think a stick blender is your best bet.  You could try a different or better brand too. If you're making huge batches I've also seen people using paint stirrers (like the pros use - it's attached to a drill bit or something)   

I tried this at first and it was a real PITA.  It takes forever to grate, and the outcome is pretty ugly. Mine looked like cat vomit  and it was too soft.

You're much better off with a base. 

I would do it individually too. 4 pounds is a pretty big mold and if you're first starting out you'll want to do smaller batches so you can experiment more, have less soap (trust me, you'll have too much soap!) and save a lot of money in FO. With CP you need about 1 ounce per pound of oils. With HP I use 1/2 ounce per pound.

For molds you can go to Target and get a drawer divider, shoe box (cardboard boxes work well too) or even a small cat litter pan.

You can get Lye at Lowes for $8.00

Then all you need is a scale (try Bed, Bath and Beyond) some oils which you can get at the grocery store, and some freezer paper or a plastic bag to line your mold.

This article is great for a first timer:
http://www.millersoap.com/USAToday/SoapArtUSAToday.html

Are you thinking about doing Melt and Pour or Cold Process/Hot Process?

1) Molds: If you're doing M&P or HP you can use anything for a mold. With CP some small molds can be tricky because they lose heat too fast and you can get a partial gel.  If you're doing M&P I'd go to a craft store or even better get some cute ones online.  The choices are endless!

2) Depends on what kind of soap you're making. With M&P you can pop them out when they are hard which is usually only a short time if you're doing individual bars.

3) Curing: I wouldn't keep them in your bedroom because you can become desinsitied to the fragrances and it's not healthy.  I store all mine in the spare bedroom. The basement might be too humid and cause sweating.

4) Shelf-life:
Vitamin E oil is not a preservative, it's an antioxidant. They are very, very different things. You can add Vitamin E to base oils to prevent them from going rancid so quickly. However if you're making something that requires a preservative, like lotion or a scrub you need a preservative and not vitamin E. 

I've never heard of using a preservative in soap making though.  I keep my oils in the fridge and only buy small amounts.

If I were you I'd start with a cute mold, a quality base, and some fragrances.

HTH!