Ah, the perpetually skeptical bonaire...
Those things you mention are of course challenges but it is not an issue at in my opinion. People are flocking to work for Tesla, so the company can cherry pick the best candidates, i.e. people who are willing to work hard and do a good job. You would be amazed at the difference it makes to have a highly motivated workforce.
Over a decade ago, when I moved back to the US, I had no money and was starting a new life from scratch and willing to accept any job and work hard to make as much money as possible to get an education for myself and my wife; therefore I was highly motivated. I started working at $6/hour doing oil changes at Jiffy Lube, but then applied for a job at a window factory to load windows into trailers (back breaking work). One of the questions they asked me is if I was willing to work over-time (paid time and a half) and sometimes 7 days/week. I responded that I would love to work as much overtime as possible (which was the truth), and the interviewer looked at me like I am crazy and even said that none of the other applicants were too excited about working overtime. Needless to say I got the job, worked a lot of overtime, and still kept my other job at Jiffy Lube. A year later my wife and I were able to start back college in part thanks to the money we saved over that year; still had to work full-time going through school though.
I am confident that Tesla also has plenty of motivated applicants and it shows in the interview process. Once they pick the best candidates, their growing pains will be smaller than other growth companies experience.
Elon also said that other OEM's are ready to ramp up and the only thing holding them back is the battery supply.
And the growth will be organic from 20k to 40k to 80k... It is not like they are going to ramp up to 100k annualized rate over night.
Staffing is the least of my concerns when it comes to Tesla.