This would depend on your goals and language skills.

My goal is to be a strategic leader and manage technology, innovation and related investments. So basically a strategic manager in manufacturing/tech sector.

I still have some time to learn German before I start one of these courses next. And I would start doing it as soon as I get an admit (if)...

Obviously one cannot learn German more than half way between now and the next start date of these degrees. And you won't improve your German while studying in English with other foreigners.

Maybe a one year DSH course followed by an MSc taught in German? To lead people, you need to be able to speak to them.

This depends on you, that what you want in life, what your goal and what is a command on your language?

Do you think I can get into ESMT with a 660 GMAT? I can speak basic German.

If you are on a par with their admitted candidates, then probably.

The average GMAT score there is 640, so assuming you are in the ballpark for the other factors, then a 660 is a good score. (That's assuming you have around 7 years of work experience, which is what the average there is at the moment).

6 years of work experience here.

Please guide for the selection of institutes.
Frankfurt SFM, ESMT, WHU, MBS

Since, I'm an engineering graduate with working experience of 9 years (3 years with Siemens) and have to target engineering firm with a strategic management career.

Frankfurt is strongest for finance. ESMT seems rather far from the big engineering centres along the Rhine. I would focus on Mannheim and WHU.

I am interested in Emba to move to Germany in multinational, I am tax advisor with LLM in International tax law. Which Emba?

Partly this depends on the quality and length of your work experience.
- The best programmes will require solid and senior managerial experience: IESE in Munich; ESCP and ESMT in Berlin and WHU in Duesseldorf.
- Under them, some solid programmes might be a better fit: Mannheim, the Frankfurt School, the Cologne-Rotterdam Executive MBA. Personally, I think Köln and Mannheim stand out as top state universities with strong law schools: German lawyers train mostly at state universities, after all.
You can read more about them at http://rankings.ft.com/businessschoolrankings/executive-mba-ranking-2019

Below these executive programmes, there are part-time MBAs run by some of these schools, and also by HHL which are easier to get into without management experience.