I haven't messed with Forms so my suggestion may be totally off.
But, from the sound of it, I wouldn't try to do a 1:1 translation.
That is, you need to 'rewrite' the GUI portion using APEX techniques and methodology.
1st step would be to rework the PL/SQL code and separate out the Display portion from the DML portion.
ie you should have a separate procedure for Update, Insert, and Delete.... in a nice pl/sql Package.
For the 'Search', see if a simple Inter Active Report that links to a Details page will work. (enter SELECT statement, done)
On the Details page (Form on Table: point to table, done), you will remove the magically created "Automatic DML" process and create a process for each of the above PL/SQL procedures (with a condition of the button you want).
All of my apps are like this. (custom pl/sql package for DML activities.)