lol, just helpin' out is what I'm doing :)
Okay, I need to tell you about cycling at some point to, I'll probably just PM you since it will practically be a novel >< There is also a Sticky on the Nitrogen Cycle in the Betta Care section I believe if you would like to check that out.
And yes plants will do just fine in gravel. That's all I had before I switched to sand and my plants were good :) Bushy ones are great for him. I don't know if you've got any Local stores around you, I find my Betta's love Water Sprite, it's a floating plant, can also be buried, but my boys and girls sleep in their floaters and they love it! You can also float Hornwort which another bushy sort of stem plant. But I don't think PetSmart will have those, but it's worth a look!
And no, it shouldn't stress him out to plant them, he also might just be observing you as well. Betta's love their interaction with people and are very curious creatures, so I wouldn't be surprised if he was just watching you do whatever you do haha.
You *may* need some sort of liquid fertilizer down the road for the plants if they don't get all the nutrients, also some of the plants like Anubias and Swords and Crypts might "melt" their leaves when you put them in, but that's alright, they are just adjusting to your water. Generally they are grown out of water so it's kind of a shock to their system when you submerge them, but they will be fine given time.
As for Liquid Ferts, I use API LeafZone and it's worked fine for me, also SeaChem's Flourish is good, don't get Flourish Excel though, that's something different. If it say's "Fertilizer" on it, it's good.
Also I would only use the Freeze-dried stuff once a week. It's basically the equivalent to feeding a child chocolate all the time haha. It's packed high in protein but lacks every thing else a Betta needs. If you find it convenient, you could pick him up some Omega One Betta Pellets or New Life Spectrum Betta Pellets. Those are the two most recommended pellets on here since they aren't filled with things like wheat, grains and corns, the things Betta's will get constipated off of. But what you have is alright for now if you want to hold off.
And I think that's good for now, I can't think of anything else that you *need* per se. Oh, also for cycling which I will PM you about later, the more plants you have in there, the easier it is. Generally fast growing plants like Anacharis, Hornwort, Cabomda, Water Wisteria (I know Petsmart usually has those in tubes you can find), Ludwigia and Rotala are good plants to do for that. Basically if you've got a lot of plants you don't have to worry about levels of ammonia, nitrite and nitrate getting too high because the plants kind of suck it all up. But I'll talk more about that in the PM. However if you're on tight budgets or anything, don't feel like you have to get lots of plants, there are other ways to cycle it and he'll be fine.
For stress relievers, the best thing you can do is just keep the lights off, you can also throw a towel over it or something so that he's in complete darkness but he'll be fine like that.
Alright, I think I answered everything....oh! And make sure the turkey baster is new and has never seen soap, soap is very bad for our fish! They do sell the "Betta Basters" at Pet smart, it's literally the same thing just marketed for Bettas. However I never actually looked into what a turkey baster actually costs but I know the Betta sucker is only like $2.12 or something like that. But either way, it does the same thing lol.
EDIT: Sorry for the novel again