From your questions it seems that you are forgetting the crossover which is different from EQ. For good sub integration you need to High pass the main speakers and low pass the subs. Low pass is not a problem as almost all subs have this capability built in. For the high pass there are several ways of implementing as highlighted in point 4 below.
1) I would go for the Genelecs or Neumanns if you have the budget. Advantages include bass response, dynamic capability and reliability, none of which are reflected in the score with EQ and a sub. Spins and preference scores are good indicators but aren't designed to capture every aspect of speaker performance. Also every Genelec will measure the same (to within limits of audibility), I think it would be harder to reproduce Erin's EQ results without measurement equipment with the Neumi. Remember Erin measured this one then gave feedback to the manufacture , then they changed the EQ, then he stuffed the ports.
2) 8030C is analog and would be a better option in the nearfield if you are using a sub. Without a sub or if you listen very loud, 8040 would be better but it's pretty big for a desktop. they are similar in overall sound other than bass extension and volume capability
3) no, no special synergy with Genelec subs especially of not using Genelec room correction. Genelec subs are nice but expensive for what you get.
4) If using a sub you need to implement a crossover and need 3 analog outs or 2 separate digital outs. For crossover you can use, a miniDSP flex, software and a 3-4 channel DAC, get a studio sub that has a built in crossover (both high pass and low pass)
5) I think MiniDSP is the best option around considering cost, quality, and features
6) you could use an analog crossover and EQ but this would be a suboptimal and clunky solution, Can't think of a good reason to do this.
Take a took at the distorion plots for the Neumi vs Genelec, The genelec has 20dB plus better distortion and will work right out of the box. The Neumi needs its ports stuffed, lots of EQ and a pretty high crossover frequency.