On MVC

[eluser]behnampmdg3[/eluser]
Hello; I have 3 questions I appreciate if anyone helps.
1 - Is there any design mistakes I am making here? Also little things like "where is the best place to use htmlentities?" Model view or controller? I'm not sure.
2 - What is the right way of making models? For example is it the right thing to have every member related method in one model? Or is it right to have one separate model per method?
3 - Do you see any obvious security holes?
This is one page and this is the other in case you need to see what it looks like.

It doesnt let me post all the code, so Im gonna post it under this as a reply
Thank you