I agree with Matherfish that what you received is undoubtedly a N. 'Wanvisa', but there are other considerations. According to Perry Slocum, the waterlily Latour-Marliac hybridized and named N. 'Indiana' is classified as a small, changeable waterlily and with 5" pads and a 30" leaf spread, and is perfectly suitable for a tub garden of the dimensions you list. Conversely, the originator of N. 'Wanvisa', Dr. N. Nopchai Charnsilpa, reports it is a sport of N. 'Joey Tomocik, which is a large lily with 8"-10" pads and a potential spread of 4'-5' and will not be nearly as happy in the same tub garden.
The bigger issue is...the reason these "mix-ups" are so common in the waterlily hobby is that hobbyists so often say they are happy with the "mixed-up results". I have grown both waterlilies in question and 'Wanvisa' propagates much more aggressively than 'Indiana'....by way or provenance, my 'Wanvisa' was received from Dr. N. Nopchai Charnsilpa and the 'Indiana' from Dr. Kirk Strawn, and the above observations are mine and not those of Perry Slocum . As result of the more prolific propagation, lesser than ethical growers are tempted to send the easier grown varieties, rather than miss a sale. My point being, while I am glad you are satisfied and I am not questioning the ethics of your supplier; I still suggest you alert your supplier to the mistake and ask it be rectified. Until the consumer stands up and demands they get what they paid for, the mistakes will never end. Would you accept a cheaper Chevy truck when you paid for a GMC...I know, not quite an analogous situation, but still let them know about the mistake, so they can correct future problems...which may be as simple as educating their employees. I am so adamant on this issue that if they want you to return the 'Wanvisa' you are satisfied with, PM me and I will happily provide both a replacement 'Wanvisa' and pay the return postage in order for you to receive the 'Indiana. It is just wrong to hear so many people say "it isn't the lily I wanted and ordered, but I like it anyway". Not to be contentious...but that is the attitude that fuels all the counterfeit markets....it is not what I wanted, but it is nice, so I'll accept it anyway. Please, demand you get what you ordered!
Truth is not what you want it to be; it is what it is. And you must bend to its power or live a lie.”― Miyamoto Musashi
"Knowledge speaks, but wisdom listens." ~ Jimi Hendrix
“The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.”― Stephen Hawking
Craig