Those letters spell celebration.
No word contains only the letters f t and h. A word that contains all 3 in that order is faith.
There are no words that contain all of those letters.
quarts
Rearranged, it spells tantalize.
Upstage.
Saltwater is a word. It contains the letters AWATELRST.
Ditty, ditsy, dotty
Unfortunately, none in the English language. The largest word with IIVAU, is VIA and with the T added, it's VITA or VATU. There are none with 5 letters.
One word that fits your criteria is "distant." It starts with the letter 'd,' ends with 't,' and contains seven letters.
Mistletoe.
The word you are looking for is "defeat." It contains all the letters d, e, f, o, t, and u, along with the letter b, forming a coherent word.
One word you can make using the letters a, a, a, e, i, b, c, h, l, l, p, and t is "alphabetical." This word contains all the given letters and is a valid English word.