As you have seen I think most of our historic teachings came before Uriah Smith, Ellen White or even William Miller.
So what did Ellen White believe then?
I went over this once before

Daniel 12

Our historic teaching is that the 1290 and 1335 days are in the past which is found in Daniel 12.
But what did Ellen White say about Daniel 12?

A wonderful connection is seen between the universe of heaven and this world. The things revealed to Daniel were afterward complemented by the revelation made to John on the Isle of Patmos. These two books should be carefully studied. Twice Daniel inquired, How long shall it be to the end of time? {TM 114.6}

Ellen White says Daniel is asking about the End Of Time not the Time Of The End.
Daniel was just told about Michael standing up, the time of trouble, the special resurrection and a sealed book.
Is your next question going to be when is the time of the end or when is the end of time?
What do you think Daniel wanted to know.?
According to our historic teaching the answer was 1798 and 1844.
I think Ellen White understood differently.

Trumpets

Our historic teaching is that the trumpets are periods of time leading up from the time of John until Jesus comes again.
What did Ellen White say?

Solemn events before us are yet to transpire. Trumpet after trumpet is to be sounded; vial after vial poured out one after another upon the inhabitants of the earth.—Selected Messages 3:426 (1890). {LDE 238.1}

That don't sound like historic talk to me.
Many try to say she is not talking about the Seven Trumpets of Revelation.
I don't know how anyone could you think that, in the same breath she uses trumpets and vials.

Revelation 11 or the Six Trumpet

Our historic teaching is that this is
What did Ellen White say?

Let all who would understand the meaning of these things read the eleventh chapter of Revelation. Read every verse, and learn the things that are yet to take place in the cities. Read also the scenes portrayed in the eighteenth chapter of the same book. MR 1518 (May 10, 1906). {LDE 95.4}

Does that sound like historic teaching to you?

Seven Thunders

After these seven thunders uttered their voices, the injunction comes to John as to Daniel in regard to the little book: “Seal up those things which the seven thunders uttered.” These relate to future events which will be disclosed in their order. Daniel shall stand in his lot at the end of the days. John sees the little book unsealed. Then Daniel’s prophecies have their proper place in the first, second, and third angels’ messages to be given to the world. The unsealing of the little book was the message in relation to time. {7BC 971.4}