Your profile says VA.. I don't know if the DC area is travellable for you but there are 3 decent clubs there that might interest you.
CCA - Capital Cichlid Association (primarily cichlids)
PVAS - Potomac Valley Aquarium Society (all types of aquariums)
GWAPA - Greater Washington Aquarium Society (primarily plants)
I know there's one in Richmond, VA
JRAS - James River Aquarium Society - also general aquariums.
I'm not sure about anything further west in the state, but hopefully you can find something; it's often a lot more interesting to meet folks in person and they can give suggestions for local places to go/shop.
I'm personally a member of GWAPA, but there's lots of crossover between the 3 DC clubs and the folks down there are all great people.
And for ID purposes -
Hornwort - Ceratophyllum demersum -
https://en.m.wikipedia.org/wiki/Ceratophyllum_demersum
Guppy grass - Najas guadalupensis -
https://aquariumbreeder.com/guppy-grass-care-guide-planting-growing-and-propagation/
My experience was that hornwort didn't do too well in soft water, and shed all it's needles and died off within 2-4 weeks in my aquarium if the pH was low.
But your experience may vary.
As for the sword, they are heavy root feeders and if it's a new aquarium it likely needs some sort of fertilization at its roots. Root tabs/capsules are the most common,you can DIY or buy from a store, just make sure they are complete and contain micro and macro nutrients and put a couple in the substrate by the roots of the sword (I would avoid the center right below the crown of the plant and try not to touch the roots if posdible)
But the best of luck with plants and all the fish.