First, and most important at this point is to decide which training systems you are going to use. This being said, year 1 is to training, year 2 ,to grow stronger vine, maybe in year3 it will fruit.
The easiestis to ask the supplier for recommending a prune style because each grape cultivar may require different prune style.
Your location determines the diseases/ pests pressure therefore determines your spray schedule. Your local extensions office should be a good sources to ask.
If the grapes are for my own consumption, I would grow them as organic as possible, using minimum spray and spray less chemicals on the plants. I would not use growth hormone on the fruits I plan to eat
Previous Nurseries I worked at propagated and sold bare-root grapevines that were 1yr or 2yr in the field for growing. The 2 yr vines were definitely fatter trunk size to start with. But both sizes grow like weeds.
Are yours container grown or bare-root? If bare-root, the first year I would expect a lot of root growth and some top growth. More top growth the 2nd year with perhaps a few bunches of grapes being produced. It really takes about 3 years from bare-root before you get even a small crop.
The BIG thing the first two years is training to whatever growing system you use for grapes in your area. For me, I use the 4 arm kniffen system on the labrusa grapes I grow. I am no authority on growing systems for seedless grapes in other areas. Nobody seems to use the kniffen system much anymore. It works well for me. But some grape varieties produce more if grown with other training systems.
Insect and disease? For me in Wisconsin, grape berry moth is my nemesis. Not sure if an issue in your area of the country. I also can get downy mildew and black rot at times. Again your area could be totally different on insect/disease pressure. One year I got hit hard in spring on grape flea beetles sucking the juice out of the expanding buds. Not many grapes that year. They were never an issue again (actually they are a pretty insect with their emerald green color).
For me, I hit them with fungicides at certain times of the season and an insecticide too. Yet others I know NEVER spray anything and seem to get grapes most years. Not me, the grape berry moth would wipe me out if I did not spray. Tried that and lost the battle if I do not spray for them. Where I am, we get usually 2 generations per season.
Thompson seedless is probably only zone 7 hardy, so you will be pushing it in 6a. It also needs to be grafted (unless you are in an area without much phylloxera issues-like very sandy soil), and will need LOTs of spraying anywhere in the eastern US for fungal diseases. I think that Ladyfinger grape is also pure V. vinifera, so hardiness and lack of disease resistance, and need for grafting will be similar to Thompson. Fungicide sprays need to be weekly unless in drought conditions.
Einset and Glenora are plenty hardy, and don’t need grafting, but you will need to keep black rot under control. That mainly involves spraying during bloom and just after bloom, which is when berries get infected.
Thompson Seedless typically needs to be cane pruned to be fruitful. All seedless grapes other than Black Corinth have Thompson, aka Sultanina, in their ancestry and have varying degrees of ability to fruit from spurs. Einset is a quarter Thompson and can probably be cane or spur pruned. Glendora is half Black Monukka, which can be pruned either way, so I would guess the same is true.
I work for a commercial vineyard. We prune bareroot vines down to two buds after planting and train up a single shoot. If watered and fertilized well, it is possible to get a few clusters the following growing season, but I would focus on developing a strong vine rather than trying to get fruit as soon as possible.
As others have said, the training system you use will dictate how you treat the vines the first few years. Thompson and Ladyfinger are unlikely to be fully hardy in your area.
Einset, Thompson, and Ladyfinger are susceptible to powdery mildew. Here in California, the standard organic treatment is powdered sulfur, but that needs reapplication every two weeks and after rain.
Ladyfinger is seeded and will make full-sized berries without treatment. Einset and Glendora were selected for decent sized berries despite being seedless and may react unpredictably to gibberellin treatment.
That’s unfortunate about Thompson and Ladyfinger. I see now that while the site I purchased from designates Thompson as within my growing, other sites list it outside of my zone… with this in mind I don’t have much hope for its survival. Lady finger is also listed as 6, but maybe I should just keep it small in a pot?