Welcome, Kalem.  

I'm one of the folks Logan mentioned who is working on a purely written language, jointly with Sai, namely UNLWS .
One of its significant spiritual inspirations was Heptapod B which Ted Chiang limns in his _The Story of your Life_, which if you've not read it might make a good source of inspiration for you.  

On Mon, 15 Sep 2014 20:29:09 -0700, Kalem Tysick <[log in to unmask]> wrote:

>Here are the alphabets and the base 16 numeral system (made with PBS' Alphabet Synthesis Machine):

My first question would be this: have you considered alternatives to having alphabets?  Alphabets are relatively convenient for writing spoken languages because phonologies of spoken languages tend to resolve very nicely into sequences of discrete units.  But if your language is purely visual, this force towards discretisation and linearisation need not exist.  

As an illustrative example of what an old written-only language in pen and paper might look like structurally, consider Chinese characters.  They have many recurrent elements at several levels of structure, certainly, but individual levels are not *linearly* decomposible into units, and it's harder to nail down what the inventory of units is.  

On the other hand, maybe you meant that the alphabets are for writing down the colour and texture patterns, and it's the latter that's the primary more of communication?  In that case, maybe the colour-texture language would be perceptually discretised and sequenced for the aliens, and then it would be reasonable to have alphabets.   

>What do you think I should do for grammar and/or syntax for these languages?

If you're at a loss for interesting ideas, you could go read some grammars of interesting human languages to get the creative juices flowing...