What other words can I use besides worker, crew, team, or my guy? I need to find words that work for a singular person and then words that would describe a group of people hired to work or perform a service.
Normally you would use the title of the task that they have been hired to perform. So if you have hired them to build a house one individual is "a builder" and the group are "builders".
There are more generic terms like "labourer" (any manual worker) or "clerk" (office worker).
If you need to be completely generic then "worker" is probably the best term. If they are hired to do a specific task, they might be contract workers. If they are permanent, then they are members of staff.
Your other words don't specify "a person hired to do a task". A "team" is just group of people doing something together. And "my guy" is just a man - the phrase has nothing to do with work.
We hired a team of builders to construct the new laboratory.
It took 20 labourers a week to clear the ditch.
There are 40 members of staff at the school, including 25 teachers.
Every worker at the company must read and sign the health and safety policy.
Way back in ancient times, we used to use things called "books", made out of paper.
One of those books, essential on every desk, was Roget's Thesaurus. Like a dictionary it listed English words, but rather than alphabetically, it categorized them by meaning.
At the back was an index, with entries like:
worker bee 414.38 doer 718.1 hireling 750.3 termite 414.37 types of 718.18 working person 718.2
One would choose the category that matches the use of the word that one is interested in, and turn to the indicated section number. That section would list all the words with similar meanings. Even better, the nearby sections would have words with related but different meanings.
A couple of minutes would answer your question with many times as much information as you actually need, and you'd be able to find the perfect word.
A thesaurus took a bit of effort to use, but the world was wonderful.
Then, in the 1970s, some publishers realized that this was more work than most people wanted to do, so they started publishing their thesaurus "in dictionary form". Rather than going through an index, one could go directly to the appropriate entry. The entries would of course be much smaller, and the idea of finding nearby concepts went away, but it was easier to use, so that's what everyone (including those that previously couldn't understand a real thesaurus) started buying. Sales went way up and the useful version of the book went out of fashion.
Then the web came along, and those semi-useful books were in turn replaced by web pages that simply list a small number of synonyms. These are even less useful, but they are fast and easy to use, so who cares.
Visit some used bookstores and look for an old Roget's Thesaurus that is not "in dictionary form". Make sure it has everything listed by section number, not by alphabetical order.
Then buy it and treasure it for the rest of your life.