Tangband W69-1042 + W3-315E F.A.S.T. project

I'm looking forward to give my W3-315E some bass encouragement.
The Tangband W69-1042 Bass driver is my favourite choice for this job:

The W69 can be build in a realtively small enclosure (~30 Liter volume)
Bassreflex type and should deliver good response down to 40 Hz or even lower.

Now, I'd need some help for passive crossover calculations.
The crossover frequency should be around 200Hz-300Hz.
The W69 will be mounted on the front panel (not in the side).

My questions:
Which kind of filter sould be useful: 6dB or 12dB for both chassis ?
Is there any need for impedance linearisation ?
For the W3-315E I already use a LCR circuit (0,56mH, 6,8µF, 6,8 Ohm) which I want to take with for the new crossover.

I'm afraid of high valued coils for the bass driver, which will lead to high costs for electronic parts, maybe switch over to an active implementation
with an active crossover like Behringer DCX2496 which gives more abilities to change values later ?

Does active crossover (with opamps and many electronis parts inside) influence the sound in bad way (compared to simple passive crossover design)?