My chimney definitely needs some new flashing around it. I have a leak
and water has gotten into the attic area and started to cause the
plywood below the chimney to warp and bend.
The roof has two layers of shingles on the roof. The 2nd layer is less
than 10 years old.

At this time, I would like to stop the leakage with getting the
flashing replaced. I am thinking that the warped plywood can be
replaced when we reshingle again in 10 years or so.

Our chimney "top" above the roofline has a "brick look" asbestos
material. It seems to be in good shape.

I have gotten a couple of suggestions and not sure which is "most
sound". Naturally, my goal is to get the remaining 10 years left out
of the existing roof. Which sounds like the best solution?

1) Tar/seal around the chimney. (Cheap $100 - but will it work and for
how long?)
2) Replace asbestos chimney top with aluminum/stainless chimney through
roof and replace entire section of roof. Roof replacement = $1300
(doesn't include new chimney cost).
3) Reflash around existing chimney (Inexpensive $250 - should work -
new leaks to be concerned about? I asked the roofer about removing
existing shingles and he said he should be able to tuck the flashing
under the existing shingles (keep in mind there are two layers!). I
have a feeling this isn't going to work well - but he didn't think the
chimney top brick stuff was asbestos.

I know option #2 is probably the BEST solution to ultimately fix the
situation, but I dont really want to put up a new roof when the
existing roof still has half its life left.

Any ideas, suggestions?
Dom