You say that you are a beginner at SEO.  That's honest.

However, you are jumping in with keyword research, registering domains, building landing pages, giving sites a diverse appearance.

I don't agree with a lot of your strategy.

In my opinion, it would be a good idea to put on the brakes.

Before you sink more of your time into things that are probably not going to work well it would be a good idea to increase your knowledge or hire someone who can get you moving with a solid plan.  Your team  might also need a referee.

If you have not done so, consider reading. Advanced Google Adwords by Brad Geddes.   I have read it twice, and reread some parts of it many times.  Best book anywhere for adwords.

If you are spending major money on PPC then you must attend Brad's Adwords Seminars.  This is  two days of intense training for Adwords.  This is not a fluffy seminar.  The first morning covers the basics and then you get deep into spreadsheet math.

Adwords is not a word game, it is a math game.   This is not a seminar where you will sit, sip coffee, fart and go home an expert.  You are going to do lots of math that will require you to think VERY HARD.  But if you can learn what is being taught you will definitely make a lot more money and your competitors will be making a lot less.

Making money with Adwords is very difficult for me.  More difficult than SEO.  Why?  You are competing against the entire resources of your competitor.  They might have lower cost inventory, cheaper shipping, cheaper labor.   If they get 60% off MSRP and you get 40% off MSRP then they can spend that 20% on Adwords and still make the same profit that you do.  But if you bid enough to compete with them then you lost 20% off the top, then pay credit card fees, shipping from manufacturer to you, labor, shipping supplies.  You just made zero profit.

My suppliers are often the ones who bid against me on adwords.  Really really hard to beat them when they have huge cost and expense advantages.

Like I say, Adwords is a game for the people are really good at math, have highly skilled people making a website that converts customers like greased pigs, and are cut-throat competitors on costs and expenses.

You better know your numbers or you will lose your shirt.

Please call all of my competitors and sell them this service.

I would place this blog on the primary domain.  Then all of the value from links that hit the blog will help power the primary site.

I believe that the job of the SEO is to ask the client "where do you want to be visible" and inform them "where you can be visible".... then let them know that visibility there will never happen unless they have content that positions them for the target keywords.

So, I would let them know what it will take to be visible for some of their important keywords.

Nobody knows for sure but I am betting that diminishing returns begin at about the second link.

However, if you are getting links from the Pope's site then you can probably get an awful lot of them before the value depletes to a really low level.

Here is a philosophy that I have... (I am not trying to be a wise guy... just sayin'....)

I don't pay a lot of attention to the methods used by my competitors.  Instead I decide what I think will work best for me and then do it.

Right now I have pages on my site that I don't want in the search engines index.  So I have code on them as follows....

name="robots" content="noindex, follow" />

I believe that code keeps them out of the index but allows pagerank to flow through them to other pages.  I offer that here so that anyone can tell me if it is wrong.

I welcome anyone who can set me straight or anyone who can suggest a better method.

However, I am not going to look at my competitors and try to figure out what they are doing because there is a very good chance that they don't know what they are doing.  (I think your competitors don't know what they are doing.)

I have absolutely no problem with doing things differently from my competitors.  In fact I think that mimicking them is the best way to finish behind them.