I think I've cracked it. I honestly feel like the biggest idiot because the plethora of sources of information about on modes has done nothing but confuse me. Twice I've thought I'd "had it" but apparently not. Now I feel I understand. My problem hasn't been realizing what a mode is, or how they work etc. but rather, constructing a chord progression for each mode. I hope what I'm posting is a little different from a typical modal question so as to give you a break. Here we go...(Working from Guni's article)

A Aeolian is from the key of Cmajor. So, if I take the three major triads from Cmajor and have an A note added to each of those three triads (to keep that 'aeolian' sound) I have the following:

Cmaj triad: C, E, G. With the A note this becomes Cmaj/A, or in simpler terms, Amin7.
Fmaj triad: F, A, C. With the A note, this is still Fmaj.
Gmaj triad: G, B, D. With the A note, this becomes Gmaj/A, or, Gsus2.

So then if I create a small chord progression/vamp with the chords Amin7, Fmaj and Gsus2, I technically have an A Aeolian progression there, correct?

Just to make sure I've gone about this right, here's another example I've worked out, this time, A Phrygian:

A Phrygian is from the key of Fmaj. Thus we get the three major triads, Fmaj, Bbmaj, and Cmaj. Again, with the A note to keep that Phrygian sound blasting, we get:

Fmaj triad: F, A, C. With the A note, this is still Fmaj.
Bbmaj triad: Bb, D, F. With the A note, this becomes Bbmaj7.
Cmaj triad: C, E, G. With the A note, this becomes Amin7.

So then again, a vamp/progression using those chords would technically be a phrygian progression?

Now I'm about 90% sure I'm right with what I've posted above.

Now, keeping with my examples, the only chords I've used to create modal progressions are the I, IV and V from their respective tonic key. Can other chords be used? I know that the chords mentioned can be embellished in various ways, but how about different chords? If I'm correct in my thinking, to introduce new chords into these types of progressions, would this work by substituting existing chords?

You should know by now I hate to bring this topic up that so many of you must hate seeing, but I feel I've finally come to a close on it now.

Thanks in advance,
Nick