How to structure micro-services

Hi, I have a website which is becoming an unmanageable monolith.

I am looking into breaking it up in the various micro-services using Lumen however I am a bit unsure about the structure, especially when it comes to authentication.

Brief overview of the website.

Companies pay a monthly subscription to have a profile (like a directory). They have the ability to post news, job adverts etc. There are also news items posted by the website owner (I am calling it editorial).

Here are my questions:

1. Should I use Laravel as a the main framework to deal with authentication/routes/views etc. and various instances of Lumen for obtaining data the micro services (E.g. News)?

2. How would I authenticate (Using standard user password) so that only those with a subscription can post to the news micro-service?

3. How would I host this? As various separate applications (Running off different domain/subdomain endpoints e.g. news.tld.com, companies.tld.com) with separate databases? Would this really be faster then having a monolith?

Any guidance as I start my journey would be appreciated.

Thanks

M