Well there are a few problems,
One is we need to get 318ti org off vbulletin 3.8, PHP 7.2 wont work with it, but 7.0 might. If you get a different software, like Xenforo it will go a long way.
Second is the site is already hijacked according to the securi test. ( [url]https://sitecheck.sucuri.net/[/
How much space / bandwidth are you needing every month? $180 a month is just too much going on for the little activity we do get here. there are much better options these days, even VPN would go far.
Now I would say dont prune down the users or close down anything just yet. Best to hire someone to transfer the whole thing to a different host and software. The sites security need to be upgraded, probably also a CDN/ hosted over the cloud. Will likely be a $1K - $2K budget job for that alone. I say just try to retain as much as you can, most of can be made to work if you find the right persons.
So there it is, and if you need some ideas or resources, dont be shy to ask me, and if you absolutely want to give up, consider just passing it on to someone, if not me then someone else, but don't close it and delete everything I'd say.