There is no penalty or loss for changing an IP address. There are many legitimat reasons for doing that. IP changes often occr when your host moves your site to a different server, or, when you upgrade your hosting package, or move to a different hosting service. No worries at all about new IPs.

Park A on B and redirect with explicit .htaccess.

In this situation I would become an Adwords expert while I continue an attack on organic SEO.

Have you thought about making a few videos?  I believe that opening a youtube channel and getting a few videos up and one on your homepage can help your rankings.

How about a video on "renting a limousine - how to get what's right for you"?  This  would not be promotion of your service and would not contain any chest thumping... just explaining and showing all about limousine rentals to people who have never rented before.

Also, have you gotten your site ranking in local search?

If you are creating strong content for a weak site then promote that content where a one-sentence post about it will capture a lot of attention.

Promoting it on sites such as slashdot or reddit or digg can be valuable.

If you give away great articles and they are posted on other stronger websites then those other websites will outrank you, steal your traffic and get all of your link, like, tweet, etc attention.  This is feeding your competitors and creating new competitors.

Be patient as your site accumulates power and don't be so tempted to give away your most important assets for a small and short-term gain.

For example right now I have an H1 tag with my main targeted keywords on every page on my site, even if the pages content doesn't necessarily match the keywords in the H1 tag.

Most likely, you will be able to improve the search engine traffic of most pages by making the H1 text match the topic of your PAGE.

It all depends on the quality....

... if this content is best-on-the-web then publish it only on your site but promote it everywhere

... if this content is really good then publish it only on your site, promote it there conspicuously, promote it to your closest allies

... if this content is low quality then offer it to your competitor to post on his website

There is a lack of consensus in that thread... so what you read becomes less important than what you decide to believe. 

will Google recognize that i'm only promoting our own websites and see this as a bad thing?

Google is really smart and knows that people have been manufacturing links this way for a long time.

In my opinion, a better idea would be to merge all of these little websites into one big kickass site.

You can do more damage to the competitor with one battleship than you can with ten potato guns.

Also... one big kickass site with tons of information and resources usually impresses the visitor more than a hotdog stand with a lot of links to similar websites.

These are long-tail keyword domains.  Yes, I would allow them to expire and allow my competitors use them in a strategy that is ineffective.

I would let those domains expire and buy beer with the money savings.  Then spend the time savings improving my primary website.