I don't know if the default messaging app alows you to send text or pic's to several people at once, but i do know handcent does which is what i use. You can download handcent from the market place. when you want to forward a text or something like that you long press on the message and select forward then it will open up a fresh window and on the right hand side of where you would put a name you will see a small blue (i think is the correct color) plus sign. click that and it opens up your contact list at which time you can select everyone you want to send the text to and then click the back button and hit send...sounds hard but its now. As for pic's you just click on the pic and it will give you some opitons one being share and the other being set ass. If you select share it will open up several other options like share via text, email, post to facebook ect....if you select share text it will pull up what ever text app you are using and resize the pic if need be, and then you click the blue plus sign on the right side of where the names go and click the names you want to send it to and then hit back button and hit send...remember sending pic's take longer to send then normal text...so it might take a little bit.
As far as closing out apps, well some apps you have to hit menu while in the app and select close to truly close them, but most apps you just hit the home button. But again SOME apps you do have to hit the menu button and select close or the app will stay running in the back ground ever if you hit home, and that will drain your battery.
I have found that the phone it self comes fairly basic but with the market and all the apps you have to pick from you can make the phone do what ever it is you want. I don't use many of the default phone features but rather use apps from the market for just about everything i use my phone for.
Good luck
