I am glad to offer assistance! Glad to hear the hotel will pick you up!
In these times, we don't know what or how the world will look like in a month or two down the road, but it shouldn't have us living in fear. Planning ahead for good times keeps us sane and alive, so go ahead and enjoy the planning as well for your birthday!
Only thing I recommend is to always ask info on cancellation policies and whatnot as you book, especially if you put down money to make reservations, just in case you were to have need of them. Most people are pretty flexible at the moment, it's the only way to be from both ends to make sure we can move on forward in these times.
As far as luggage storage on trains: I would NEVER leave my suitcases away from where I am seated, not even on the first class wagons, but never on regional trains. If you don't have them constantly under your watchful eye, they can disappear! I prefer to keep any luggage close, there is some space in between the backs of some seats that go back to back and I stick luggage in there, particularly bigger ones. If you have some lighter bags, there are racks overhead to place those. Under your seat in another alternative, but only if I'm seated at the start of a wagon where there is no way they could be taken from the seat behind me. If needs must, then I place them right by my legs and use up my own legroom. Always keep luggage near so that you don't have any unpleasant experiences with theft, they do occur. Better to prepare for the worst and enjoy when they don't happen, right?
As for the wine tours, in addition to Alessandro, also contact Francesco from Wine&Drive. He can drive you on general tours across the area, but since he's a sommelier, he is especially great on wine tours. He can take you to really good boutique wineries and offer extra info! I did an interview you can read here:
https://www.discovertuscany.com/tuscany-car-rental/tuscany-wine-and-drive.html
Also check out the rest of the site: in addition to this forum, the rest of the website has a lot of suggestions as to what to see and do in general across the region. Lots of ideas, you won't be able to do everything so will need to make decisions as to what you can do, especially if you don't have your own means of transport.