Hi there,
I am an expert software developer with more than two years of experience in Node.js, Python and deployment in cloud and hosted Linux servers. Here's a brief outline and estimated costs for your E-Learning platform that you can expect:
1. Hosting: if you get a full VPS with root SSH access, it can cost you between 9 - 20 USD/month. On cloud if you choose to leverage Serverless infrastructure, you can go with Pay as you Go (PAYG) plan. There are excellent free tier usage within which they will not charge and can be an excellent way to get started (I built a similar project on AWS)
2. WhatsApp integration: WhatsApp for Business is not officially provided by WhatsApp. Instead, you have two options. You can either use chat-api that will connect to an existing WhatsApp account you have on a physical device and use that; it costs over $30 per month. Or, you can use Twilio; in that case you need to buy a virtual number (5-10 USD depending on area) plus additional charges (per 200 texts outgoing if I remember correctly).
3. Searching: WikiPedia API is free and can be easily integrated. For your Wordpress site, does it have an API or does it need to be scraped?
Whichever options you choose to go forward with, I can develop the necessary solutions and I have the expertise to scale your system as you attract more and more users. Let me know what you think of my offer. Thanks for your time and consideration.