Q.Start vegetable seeds in greenhouse?
Vegetable seeds – I start them off in those Jiffy seed start kits inside the house and as they get too big for them, can I transplant them in my greenhouse and then out in the garden as they get bigger or is that too much transplanting for them?

Transplanting works well with some plants and not others. Is your greenhouse reliably 60-70 F overnight and not over 85 in the day? Since you are using a degradable pot, transplanting is less traumatic; however, I'm not convinced of the benefit of having large plants at the time of in-ground planting. It is an easier transition when a transplant is small. Smaller plants rapidly catch up in size to larger transplants.
I hope you know that some veggies should not be started inside; rather, they should be planted directly in the garden at the appropriate time. These veggies do not transplant well and there is no advantage to starting them early. Carrots, corn and beans are examples. Seed packets often have good information on when to start seeds. Here is an article with more information: https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/when-to-start-seeds.htm