Hi nyRita,
about the names:
fosterianas are a group of Tulips, almost species, but somewhat bred/hybridized. Among the cultivars in that group, the Emperors-types are popular ones.
The nice thing: they flower pretty early (compared to garden hybrids), are perennial-ish and have showy flowers.

I garden in Europe, at a lecture I went to, a very specialized garden architect recommended White Emperor as one of the few tulips that multiply in the long run and is THE most reliable.

And Sweetheart I happend to order for a large planter, about 3 y ago. After flowering I dug them up and planted them non too gently in a strip of lawn in front of our house. They get full sun and bake in the summer, the strip not getting irrigated.
Right now they are flowering, despite being trampeld on when emerging.

Last autumn I planted a large batch of fosterianas in our allottment and am curious how they perform in 3 or 5 years.

So, have fun with those,
bye, Lin

I've been growing Fosteriana tulips for several years and I find Flaming Purissima (flaming white Emperor) are the most reliable ones, as well as the prettiest. Haven't tried Purissima itself (white Emperor) though. The best spot for planting FP was under large deciduous trees, Western exposure - a neglected spot where fallen leaves hadn't been collected over the years, enriching the sandy soil. They thrived there (I duly watered until they were gone for the summer). That must have been over 10 years ago and I still have those tulips, albeit moved closer to the house, where there's no leaf compost and so they return in smaller quantities. FP = definitely a keeper, flowers very elegant, plants robust, bulbs multiply.

Sweetheart - they are indeed beautiful, but not as robust as FP, don't return as reliably. But they are worth replacing because of their cheerful, sunny looks.

In my Orange Emperor there was no salmon, only carrot. I found the color unsatisfactory. They were very tall.

The other ones you mentioned I haven't tried ... and I don't think I will because I like pastel colors more than basic bright yellows and reds.

My last attempt at pastel colored Fosterianas is yet to bloom and is called Albert Heijn, described as pink. I'll see when they open, hopefully by the end of April.

So far only Toronto tulips opened in my garden, the weather has been too cold and dry ...