New Member, site to buy components?

First the impedance.  No, you are not correct.  You do NOT want to try and change the impedance of any of your speakers.  Your chosen tweeter is an 8 ohms unit.  Your amplifier will be loaded by the woofer @ 4 ohms below the crossover frequency and by the tweeter @ 8 ohms above the crossover frequency.  This is how a crossover works, the speakers are not in parallel.  Do not suffer from the typical car audio misconception about seeking maximum power.  Ignore it.  You will be fine.  This is normal.

The purpose of a pad in a crossover is to match the sensitivity of the speakers.  The speakers you've chosen should work really well together without need for any pad.  The Peerless woofer is rated @ 91db, but this is at 2.83 volts into its 4-ohm impedance.  To convert that into a standard 1W/1m rating, subtract 3db so the actual rating is 88db.  The tweet you've chosen is 89db @ 1W/1m.  These ratings in effect match.

Good info from Steve above, and thanks for posting your pictures!

OK, actually the speakers ARE electrically in parallel, it's just the only time both are receiving a signal is in the crossover transition band.  As frequency rises, the woofer signal is being attenuated and the tweeter signal is increasing (in your case at 12db/octave) so the net impedance placed on the amp will never drop to what the two speakers would net in parallel.  Does that make sense?

2.83 volts = 1 watt @ 8-ohms.  2.83V = 2W @ 4-ohms.  The sensitivity difference between 1W and 2W = 3db.

You meant to say "coil" for that second formula, but speaking for myself, there are things in audio that I will gladly let stay above my head where they belong.  Those formulae are two of them. 

This chart from Rod Eliott's site may be of some help:

Use the crossover freq and the crossover orders that you have selected along with this chart to find percentage of power to each driver.  You may be starting to worry a bit too much about the varying impedance load...just my impression.   But then, that is an area my brain was not meant to get into.

That's correct.  That's why a tweeter isn't getting 100 watts at 4000 Hz.  It'll probably never get more than 10 watts of power.  The more that the frequency spectrum relies on the tweeter to produce the primary sound, the more power goes to the woofer and the less to the tweeter.  That's where the "robbing" of power due to the coils etc. come into play because of their impedance ( I think...heh heh).

er, at least I mean to say that the chart is correct.  Use it to see that at 2400 Hz the power is NOT split 50/50.

edit to add:  IIRC, this chart was used so that you can have some help in determining power values of resistors used at the various frequencies.  This showed that in most cases a 5 watt resistor is fine for the tweeter, if I remember Rod's words correctly.  http://sound.westhost.com/lr-passive.htm#7.0

Again, don't concern yourself with power utilization.  As long as your woofer and all the crossover components are rated to handle the power output from your amplifier, you are OK.  As far as the tweeter is concerned, like Steve mentioned most tweeters never see more than 8-12 watts no matter what because of the frequencies they reproduce.  There is NO point in your system where "amplifier power is shared 50/50" by the two speakers.  It will never happen, nor do you want it to happen (as you would blow your tweeter.)

Power utilization as a function of frequency is what Rob's chart that Steve posted illustrated.  If you look at that chart, 80% of the amplifier's power goes into reproducing frequencies below 2KHz.  Also, don't worry about Rob Elliot being down on inductors.  While what he says is true, he tends to exaggerate the importance of some things to reinforce his own personal biases (in this case, his bias towards preferring active filters VS passive crossovers.)

The component values I listed are standard textbook values for a Butterworth 2nd order filter @ 2400Hz into an 8-ohm tweeter.

The network you posted includes Zobel circuits for the speakers, which you will not need to concern yourself with.  It is also a crossover for two 8-ohm speakers: you are using one 8-ohm and one 4-ohm.