Upvote:1
They should be enough, because those are the minimum requirements, but obviously having all of those is no guarantee of obtaining the visa. See here for the list, from the Embassy of Guatemala in Sweden:
Business Visa
1. Valid passport.
2. Copy of the passport.
3. Recent photo.
4. Filled application form.
5. International credit card, A letter from your Bank or Travel Checks (in your name)
6. Work letter explaining your position and your annual salary.
7. Reservation of round trip ticket (and the visa of any country you transit from).
8. Invitation letter.
9. Commercial Registration of company.
10. Legalized photocopy of the passport.
11. Visa fees: US$ 50. Period of validity is 180 days
A traveler's check is a form of payment especially made for, as the name suggests, travelling. As even regular checks have become obsolete, this isn't a common method at all these days.
The commercial registration number (or certificate) is something the inviting company will provide you, it's a business certification, presumably to verify the identity of the company inviting you.