It really depends on the position. Really, in such an industry where things are changing rapidly, new products are being launched by yourself and your vendors, and of course, new technology is coming out; you really should continue to train staff all the time.
Hiring local is great, but if you can't afford to do that (office space or other reason / restriction) then remote is great too. You will have to factor in several key things when hiring remote, for example, you might have the most knowledgable tech in the world, but is he people ready? Can he answer tickets in an easy to understand way? Can he communicate?
You may have the most reliable and friendly customer service employee ever, but is his internet as reliable at home or his office? Does his phone work?
There are a ton of other things you must consider as I outlined above.
Hiring local cuts down on those problems since you would have the office, the equipment, the connection, phones etc.
Interviewing over the phone is also hard. You can't see the person, get a feeling or vibe from them. Ever had that feeling when you are around someone that something just isn't right?
Hiring should have many stages. You should pick out a short list of people you like for the job. Interview them and base if you want them to progress on how they handle the interview. Are they ready? Did they pick up the phone or did you have to call them back several times?
Then, you should pop quiz the successful ones.
When you have narrowed it down to the top 5 or even 3, you can simulate situations. Get them in front of a computer, get them to do a few hours of the hardest work that they could possibly face in that role and see if they can handle it.
90 days probation is also standard. Give them a chance to blend in, get to know you and the company.
Those who are interested in your company will have researched you and know what you do, offer and probablly stuff you didn't even think anyone knew.
I'll stop now!
Good luck.