A Kohen cannot receive an Aliyah after a non-Kohen on a regular weekday (or Rosh Chodesh), when three (or four) people are called to the Torah.

On Shabbos or Yom Tov, a Kohen may receive only the Maftir Aliyah after a non-Kohen had the previous Aliyah. (Similarly, you can give a Levi the normal Levi Aliyah, and Maftir.)

On Shabbos only, when it is permitted to add additional Aliyos, a Kohen may receive the "Acharon" Aliyah (there is no Acharon Aliyah on Yom Tov, or Yom Kippur).

When there is no Levi present, then the same Kohen may receive the first two Aliyos (on a weekday, Shabbos or Yom Tov).

Accordingly, on Yom Kippur, besides the Maftir Aliyah, there is nothing you can do to give a second Kohen or a second Levi an Aliyah. In many synagogues, additional Kohanim and Leviyim are honored by giving them the honors of opening the Aron, the honor of Hagbah (which, by the way, is considered by the Gemara to be the most important honor), the honor of Gelilah, and so on.

G'mar Chatimah Tovah, and Shanah Tovah,

Yaakov (ha'Kohen) Tavin