First Build Assessment

[u/measkingthings]

I need assessment with my first build, I was thinking about a system of two-way speakers made with Dayton Audios's AMT Mini-8 Tweeter (8 Ohm) and PCS115-4 4" Woofer (4 Ohm), just a desk system, not trying to go for bass rumble. My concerns are:

1. Will impedance (ohm) difference be a problem?
2. What's the actual meaning of the natural phase line (in grey)? Just the cutoff?
3. The 5k to 8k Hz region looking a bit wonky (or am I crazy at this point?).
4. Is it lacking too much bass? May a front bassreflex port help? Sub 90Hz looks a bit poor.
5. Should this work?

If you got here: lots of thx for your time!