yeah I couldn't do it on my own without going to an immigrations office and bringing back a form because i was on a visitors visa. Immigrations is like a 40 minute drive one way so i paid an agent 5,000 baht to avoid long lines and a drive to immigrations. Once I got to the bank the next day the agent already had several forms filled out for me. Then that generated additional forms once they were turned in and checked all the data they made a bank card then they made a checking book. Then we had to set the app up for mobile banking that took a while. All together in and out in about an hour. Not counting the previous day waiting in line and was told I needed a form from immigrations first.
i just opened an account at bangkok bank with an agent helping the teller with paperwork it still took almost 1 hour for them to make the account. Setting up the app alone took 15 minutes. The agent got paid 5,000 baht.
Everything about it is a problem. Please seek legal counsel. 1st he needs a passport unless you're going to pay him cash under the table against the law. This would put you, your company, and partners at risk.
Secondly what kind of job is this because the work permit system is in place to encourage companies to hire thai nationals. If it's a job a thai can easily do there is a high chance it won't even get approved.
If you're saying you had 60 day VISAs both times and you are entering again for the 3rd time this year by Air then no there will be no problem. If you follow the rules and don't over stay your VISA you are good. I've been to Thailand 5 times in 2 years with no issues.