First email marketing campaign

Hello,

This is my first post on the forum.

I'd like some advise on email marketing please.

I'm about to launch a site that is a platform/marketplace for a niche type of service/product.

I've spent the last month gathering email addresses for individuals and companies that offer services in this niche, so that I can invite them onto my platform.

I currently have around 70,000 email addresses.

Although I understand that this may be frowned upon, as none of these service providers have opted to receive an email from me, I think the vast majority of recipients would welcome the email.
(I am also a service provider in this niche and would be grateful of the email that I am going to send them.)

I won't be blasting on a regular basis, probably only once to inform the recipients of the new platform.


My questions are as follows.

1. What's the best way for me to make sure my list is clean? (No spam traps, dead urls etc).
Should I trust offers on freelancer platforms? How do I know they've done the job properly?

2. How to avoid my IP going on a blacklist?

3. Which mass email tool would be best for a starting budget of around $100 per month. The list should be under 70k once cleaned.
I need a service that allows me to import my own list as a text file.

4. Should I drip feed the list at say 100 emails an hour, or blast the lot in one go?

5. What risks do I face with CAN-SPAM?

Email marketing is new for me, so I'd appreciate any advise I can get, as I can't afford to employ someone at this stage.

Thanks