Always review the rules regarding PTO, insurance coverage, and the last day to use a FSA or HSA. Knowing these deadlines before quitting can make a big difference.
In the United States expect that you can't take any PTO during that two week notice period. They want to get 10 days of work out of you, and letting you take time off during those two weeks defeats the purpose.
So If the goal is to make 100% sure that you will get credit for the two weeks notice, submit the resignation during the weekend. Or very late on a Friday.
In all my years I have never seen an issue with a Monday morning resignation, but I also have not seen anything that said if less than 10 days we don't payout PTO.
I am going to assume that you are correct in your assessment regarding the two weeks notice.
Also, is it reasonable to request from HR that they not tell my boss
until I’ve had a chance to tell him myself? I have a meeting set with
him for 10 AM Monday and I’d like to speak with him before he sees my
resignation but I don’t want to wait to submit and extend my notice
period by another day.
It depends on the size of the company. In most cases I have had the employee tell their manager first, then had the manger tell HR. In many cases the employee only knows one person from HR, the one they talk to when they have a question. It isn't always clear who in HR needs to be informed. The manger probably knows better who to inform. HR only wants the written notice so they can start the checkout process.
If you start with HR, the initial part of the process might trigger a notice to your manager. They might be given a document that has to be reviewed, or something they have to confirm.
Submitting over the weekend will mean that it will be submitted electronically, and the manger may find out before the meeting. In fact I would also send an email to the manger over the weekend.