Getting it done...almost ready

If i have a project ready and coded. Is it possible to go back to blender and add other features with logic editor nodes?
Will it mess up the code, or add to it without problems?
Lets say i have shape keys working and im happy with it. If i go to the same blender file and add logic nodes (additional features), will it mess everything up?

Thank you thank you thank you….its been a joy!!!! in the end i will share my work with every one!!!!!

You can mix programming and logic nodes. But you should be careful with the access to the objects. Do not operate on the same objects from the nodes and from the code. It could be difficult to find the reason of potential problems in such concurent cases. But if you need this, you can create variable with lock-meaning and check it before the access.
See this presentation from the Blend4Web conference 2016. It is a bit outdated - some nodes now have new names (e.g. Switch Select -> Select), but in general it is still actual

Since we are at it, i have a little question thats bugging me at the end of the work. When adding material (lambert) to the object, i selected a few faces, created a new material tab and added lambert but with a different color. When i test on fast preview it renders well…then when i export to HTML they disappear…what the hell??? I just cant seem to find a solution for it. Any ideas?? Thank you again…