This has been interesting, to say the least. I have looked in Guthrie City Directories 1896 and 1898. Did not find any Docker entries. We do not have an 1899 directory. The next one is 1900. Here is the entry on page 42 "Docker, A. H., Prof. K.C. Sample room, r. 311 Oklahoma." You stated he disappeared from Kansas City in 1899. I don't know how to interpret the "Prof. K.C. Sample room" -- but could he have had samples of furniture, liquor, or some other product that he would have tried to sell? Maybe the Prof. should have been Prop. for proprietor?? Just don't know what this is without doing much more research.
1902-1903 Jennings' Guthrie city Director, page 71: "Docker A H, saloon and hotel 311 w Oklahoma, r same. Docker Mrs. Lou, laundress, r 902 w Noble."
1904-1905 Jennings; Guthrie city Directory, page 54: "Docker Albert H, wf Lou, saloon keeper, r 620 W Cleveland."
1907-1908 R. L. Polk & Co.'s Guthrie City Directory, page 84: Docker Albert H (Lou), dept sheriff, r 915 W Noble av."
Note: Albert either died about 1908, or they divorced. I checked the probate indexes and did not find anything. I didn't check the old ledgers for divorce, but they are available if you want this avenue pursued. I did not find a burial in Logan County for him.
1908-1909 R. L. Polk & Co.'s Guthrie City Directory, page 84: "Docker Mrs Lou, b 712 S 1st."
1910 R. L. Polk & Co.'s Guthrie City Directory, page 104: "Docker Lou (wid Albert H), r 310 S 3d."
1912 R. L. Polk & Co.'s Guthrie city Directory, page 81: "Docker Lou (wid Albert), seams, r 705 W Grant av."
1915 R. L. Polk & Co.'s Guthrie city Directory, page 63: "Docker Lucetta (wid Albert), seams, r 705 W Grant av."
1923 Guthrie City Directory, page 45, Docker, Albert stud h 609 W Warner"
I went to the Logan County Court House and checked school census records. There were entries as early as 1912 and the last was 1926 for Albert Docker. I did not copy all of them, but the 1912 shows the mother's name as "Lon Docker" at 705 W. Grant, Guthrie, OK. It gives his birth date as 11/2/1906, white. The 1918 school record shows the mother's name as "Luecetta Docker" and it gives the address as just Guthrie, OK. His date of birth is shown as 11/2/1906, white, male. The 1921 school census shows exactly the same as the 1918. Here's the goodie. 1926 the mother's name is shown as Lucetta Poole, address 609 W. Warner, Guthrie, OK. Albert Docker's birth date is incorrectly shown as 12/28/1800 (?). I checked the marriage indexes for a marriage of Lucetta to a Mr. Poole between 1921 and 1926 and none was found. There is a burial of a Mr. Poole in Guthrie's Summit View Cemetery which I think was 1924.
The 1920 census, Guthrie, Logan County, Supervisor's District No. 5, Enumeration District No. (can't read it), page 115, line 17, dwl. #33, fam. #33, looks like "South Fourth", Allen, Lucetta, Head, F, W, 50, D, Michigan, Canada, Michiga, labor, servant. And, line 18 is Docker, Albert, son, M, W, 13, s, South Dakota, Canada, Michigan, none.
So, there she is with another last name. Looks like Mr. Docker may have died ca 1908, she married Mr. Allen sometime between 1918 and 1920. He died, then after 1921 but before 1924, she married Mr. Poole. These are merely suppositions based on her saying she was a widow on the census and the directories saying she was a widow. I certainly can't confirm these marriages at this point.
After 1926 I cannot find them in Logan County. However, I did find an entry in the 1930 census for Albert Docker age 23 as an inmate in the Oklahoma State Penitentiary in McAlester, Bucklucky Township, Pittsburg Co., OK, page 99.

I am puzzled as to Lucetta's differing claims of age, birth places, etc. It surely does appear to be the same persons on the 1900, 1910, 1920 and 1930 even though there are discrepancies in some of the facts.

I hope this information will help shed some light on this family in Logan County, OK. good luck!