If 85...KxB?? 86.KxB and Black has INSUFFICIENT MATING MATERIAL 1/2-1/2.

If 89...Bc4+?? 90.KxB and Black has INSUFFICIENT MATING MATERIAL 1/2-1/2.

If 98...Ke2?? Stalemate 1/2-1/2.

If 99...Bd2?? Stalemate 1/2-1/2.

If 104...Bb2?? Stalemate 1/2-1/2.

If 105...Bc4?? Stalemate 1/2-1/2.

On the final move 107... any OTHER move by the dark-squared bishop is Stalemate.

107...Kc1?? is also a Stalemate 1/2-1/2.

By now, the reader should realize the importance of having youngsters practice the two bishops ending! It's a real witch to get that far and ruin a won ending.

P.S. Fredthebear usually starts a lesson reviewing:

1) Check & Checkmate,
2) Stalemate,
3) It's neither.

In most cases, the lone King is on the outer edge of the board (particularly the corner), and/or a "knight's move" away from the opposing queen. Thus, FTB's students are well-versed in Stalemate situations; they are very comfortable with the term and it's meaning. FTB writes this as a word of CAUTION...

For others, warming-up with the two bishops elementary forced checkmate could be "setting the lesson up for failure" as the student is likely to step into a Stalemate and be confused or embarrassed by it. It leaves the student starting out w/a bad feeling that s/he messed up. That's not a good way to start a chess lesson!

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and

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Two queens can easily accidently stalemate the lone king, or king plus additional units by a non-check move. With TWO queens, it is important to check continuously when in a hurry, or perhaps sacrifice one of the queens. (In most endings, checking continuously is incorrect if it gives the lone king a choice of directions.) See diagram:

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Preventing escape: The winning king takes care of the front door by using the opposition, and the two bishops take care of the back door.

103...Bb5 prevents escape out the back door.

104...Bb4 prevents escape out the back door.

105...Ba5 is an important WAITING MOVE to pass the turn.

If instead 105...Bc4?? 1/2-1/2 Stalemate.
See Stalemate Diagram - White King to move cannot make a legal move:

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Realize that stalemate occurs when a non-check move is made. The purpose of the waiting move 105...Ba5 was to allow the lone king to return to a checkable square (the opposition).

The successful checkmate pattern with the Two Minor Pieces:

It is necessary to check the lone king on the square next to the corner (in this case the a2-square). Then checkmate the lone king in the corner. Thus, the last two moves are always check by one minor piece, then check by the other minor piece. This same principle applies to K-B-N vs K checkmates as well. The knight would give check on the square next to the corner, and the bishop gives the final check in the corner. See diagram:

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The bishop prevents the backdoor escape. The kings are in opposition. The knight gives the next-to-last check next to the corner, and the bishop gives the final check to the cornered king. A waiting move may be necessary to pass the turn and properly time the next-to-last check next to the corner. This same technique applies to mating in the corner with two bishops.

My students understand the plan to cut-off the lone king from escaping the edge. Then give check-check the last two moves, one by each minor piece. Sorry for the long-winded explanation.

I don't teach two minor piece mates to beginning players to avoid frustrating them. We practice elementary mates with the queen(s) or rook(s) often so they KNOW HOW TO WIN. We also review stalemate positions and perpetual check positions and insufficient mating material positions so they are very familiar with all the ways a game of chess can end. We don't want a tricky or ignorant opponent telling them they have lost when the position is truly drawn.