Awake time is what percentage of time your processor is active. 45% means that about half the time since last boot or charge your Phone's been running. When your screen goes black, the processor doesn't automatically sleep. If it's not doing anything, it will quickly sleep but the system will wake it up when it needs to run. With phones that are this much fun to play with, 45% is about average
I'm not 100% certain, as I had to send my Eris back before the update came to it but I think the sms wakelock issue was fixed. A current Eris user needs to chime in. What happened (or happens still?) is the phone dialer got locked awake when you sent a text message. To save space and make things run smoother, HTC uses parts of the dialer code to fire up the radio and send off a text. When the HTC dialer was opened this way, it did not shut off like it was supposed to. Third party apps have to open and close the dialer a different way and the dialer knew how to shut down properly then.
Number three is a known issue. It's also very easy to fix, but the phone needs rooted. HTC has enabled their own performance throttle in the kernel. It's completely screwed up lol. It won't let the phone's cpu run at full speed unless the load is very high, and it slows the cpu down so much when load is very low (like when the phone is asleep but it's time to wake up and check for mail..) that the cpu gets pegged and the touch screen function freezes up. Once that throttle is stripped out of the kernel, and normal cpu governors are used, it goes away. And your phone works a whole lot smoother and faster when it's up and running as well.
I hope this issue is fixed with the 2.1 update, but if not as soon as the device is rooted I have you covered. There will be a very simple and easy to understand method posted to root you phone, fix the lag and freeze issues, but still run the approved OS from Verizon.