You can mix and match all day. The longer rear shocks may not be required with only 1.5" but they certainly won't hurt to have. IMO, spacers are not the best but I have run them. The top had spacer is one thing but a 2.5" spacer up front is a different animal. If you have the money, upgrade the front shocks. You'll get better ride quality, better handling, and just a much higher quality and more durable lift. At 2.5" you should really look at replacement upper control arms up front also. I'm at 3" on stock arms and it's not good lol. Only got 1* caster where you really want to be around 4* Pulls all over the place on a crowned road which is mostly due to the poor caster. I will upgrade, just not sure what I want to run. I know I will NEVER run a uniball arm though, stick with a ball joint arm. Plenty of high quality options out there and some of them actually offer a greater range of motion than uniball arms do.
As for the bumper trim, i'll try and get some pictures of mine tomorrow and post them up tomorrow night.