I do have a few suggestions. I will try to put them to you as best I can.
With all due respect, your requirement specification is a bit "woolly". I spent the past 10 minutes reading it and I'm not sure I understand (a) the problem or (b) how problem was caused and therefore (c) how to go about solving the problem.
So let's start with the problem: you have spam attacks; that little I understand. Are these attacks on a regular or infrequent basis. What kind of security to you currently have in place (user registration, forum view access, forum post access, review forum posts, SEF URLs)? Is your forum open to allow unregistered users with the ability to post messages? How easy is it for people to register as users? Why would people want to spam these sites? What are the
specific challenges/hurdles facing administrator or the moderators of the forums? How do things operate at the present?
Then there's the cause of the problem: Are the attacks launched from a specific IP address or a country, for example? What monitoring have you put in place to examine the source of the attacks. Do you perform any real-time analysis or event log monitoring? How many attacks are occurring as a percentage of total postings? Do you screen new user registrations? If you are being flooded by spambots, have you implemented antiflooding controls and captcha, for example? What features do you currently lack to control the source of these attacks?
And now for the solution: you devoted most of your request writing about solutions. Make your solution specifications shorter, to the point. Place a number next to each solution requirement, together with a rating (high/low priority; mandatory/desirable, etc.), and explain the work your contractor has to perform, not how things operate at the present.
By the way, some of the approaches you've suggested ware being considered for Kunena 1.6.