Make your estate plans as complex as necessary but as simple as possible. This helps ensure that you understand what you're doing and that your plan can be sufficiently explained to your heirs after your passing, minimizing misinterpretation.
Choose individuals to fill the offices of personal representative, trustee and guardian as you see fit. It's not a popularity contest, and it's likely best that different people serve different roles. Also consider establishing backup designees to fill those positions, in case anyone is unable or unwilling.
Yes, you can write out your will on the back of a bar napkin if you wish, but it may not be worth a lot more than the paper it's written on (and seriously, it likely won't be enforceable).
Yes, having an online or software-produced will may be (much) better than nothing, but I still can't bring myself to recommend it, and here's why: Wills are written in a different language than the one we speak. It's called legalese. Your interpreter is an attorney. We can argue all day long whether this is unjust, but it won't change the reality.