Everything for the suspension will swap over. I'd keep the aluminum rear drums and just swap the front discs from an '86-'89 Integra and use '88-'91 Civic/CRX front calipers.
The first thing you should do is add a rear sway bar since the HF never came with one. Try to pick up an OPM or Lightspeed swaybar, the Suspension Techniques sway bar is OK, but it's more of a helper bar. Keep the stock front sway bar.
Building a D15A2 will be a challenge since there are hardly any aftermarket parts left for this motor. The best thing to do is add a header (still available), dual carbs, port the head, regrind the cam and rebuild the block. The block can also be bored out to accept 1.6L D16A1 Integra pistons. You should also consider swapping in an SI tranny since th HF tranny is geared for fuel economy and the SI is geared for speed. Check out
www.redpepperracing.com for more info.