WordPress NGO website: design proposal & implementation

The first part of this job is to create a design proposal for a WordPress website including an estimate of cost. The second part will be migrating the NGO's existing WordPress site and implementing that design. I expect to award the first part within the next few days. The second part will take longer as I need to get management approval. I will create separate milestones for the first and second parts of the job so you will be paid €50-100 after delivering the design proposal document. The value of the second milestone would then be agreed. The new website must be be hosted in EU due to GDPR. The existing site has approx 20 main pages some of which have links to a collection of articles, possibly 500. There are a couple of forms, but not much else. It is essentially a brochure website. The NGO expects to have between 1,000 and 5,000 members, but few will access the site daily. The existing site has cPanel so the migration should be quite easy. Your design proposal should NOT focus on the migration, rather it should concentrate on how to implement the various plugins and customisation they would need implement membership functionality, payment of membership by credit card (four classes of member), make donations, buy things like tickets for events, distribute a newsletter by email, email marketing campaigns, etc. The design requirements are summarized in the attached. I am expecting you to create a 2-5 page document to described your design proposal. Your design should be based as much as possible on existing WordPress plugins, though doubtless some customization will be required. You should explain in the document how you would implement the customisation work with links to published examples. For example, adding fields to the membership database would be done in the same way as suggested in this article (url), the mailing service would be provided by the XYZ plugin, etc which would need to be customised as follows.... Your design document should conclude with a list of the plugins you need, their cost and the cost of setup/customising each of them as well as timescales to implement the work. It should also include the monthly running costs of the site in terms of fixed fees like hosting and transaction fees like 2.6% charge on each credit card payment. When responding to this tender please state your qualifications and experience for doing this type of work as well as implementing the design in your proposal.