Portuguese Morphology from Spanish

I've been searching for proper research about the changes Portuguese underwent from Spanish to become what it is today, but I find that most research dealing with the topic is based on certain verb forms or worded in such a way, as research papers are, that I have no idea what any of it means.

From what I have gathered in only a few weeks of Portuguese this is what I have found to generally be true:

Change in Diphthongs
There is a strong shift in accented diphthongs from Spanish to preserve pronunciation for example: El Camión  to O Caminhão.

Other prominent changes that make the diphthong change apparent are very visible in conjugation of the gerund. Verbs ending an ar conjugated in the gerund do not contain a diphthong, and are therefore in most cases conjugated exactly the same in Spanish. While er and ir verbs contain a diphthong in the gerund conjugations, which is in turn eliminated in  Portuguese.

N and M Differentiation
An "N" is Spanish will often be switched to an "M" in Portuguese. This is apparent in verbs as well as adjectives i've encountered.  An adjective may lose its "N" to an "M", but still have a highly similar pronunciation. In verbs the change is striking "son" changes to "são" and "están" to "estão." What I'll call a nasal diphthong is created to handle the case of the "N".

Removal of Ñ and substitution with silent H
The "Ñ" does not exist in Portuguese and thus leads to an interesting substitution for the sound, which is similar but not the same. A silent "H" replaces each instance in words such as, "Español" to "Espanhol" the absence of the "Ñ" almost create the sound in the silence, okay maybe not, but still the change is apparent and very evident in all words which previous contained the letter.

LL change to CH
In many Portuguese words I have noticed the switch from "ll" to "ch." For instance, "me llamo" to "me chamo" and llorar to chorar. The pronunciation remains strikingly similar, although the sounds are ever so slightly different.

Hard consontants are softened OR Change of C
Hard consonants in pronunciation such as the letter "c" are softened into things than flow off the tongue more easily. Thus, "Cocina" becomes "Cozinha." Generally, the  "c"  sound is changed to an /s/ perhaps resulting in the character "ç" to substitute for the loss.

Non-Morphological Lexical and Aural Changes
The Portuguese Lexicon has adopted many words from dialects descended from Latin, and has seen many changes to adjectives that have been adopted in other languages. the pronunciation is different and sounds similar in some ways to Italian and perhaps slightly to French. The nasal sounds are the most striking changes, but I can´t trace where they descend from.

These are my thoughts on Portuguese morphology albeit amateur, but my go at understanding the changes that have happened.

(Image Courtesy of mi amiga Sol. She graciously shared with me some images of Salta in Argentina. )