Are these sentences grammatically correct? plz apply.

I need native's intuition about Grammar(Syntax)

Insertion Test

1-1. He, however, could have been playing tennis. ( )

1-2. He could, however, have been playing tennis. ( )

1-3. He could have, however, been playing tennis. ( )

1-4. He could have been, however, playing tennis. ( )

1-5. He could have been playing, however, tennis. ( )

Pseudocleft test

2-?1. What he could have been doing is killing flies. ( )

2-2. What he could have is been killing flies. ( )

2-3. What he could is have been killing flies. ( )

Constituent Response Test

3-1. Q. What could he have been doing?

1. Playing tennis. ( )

3-2. Q. What could he have been?

1. Been playing tennis. ( )

3-3. Q. What could he do?

1. Have been playing tennis. ( )

V'-deletion Test

4-1. He could have been playing tennis pleasantly, but she could unpleasantly. ( )

4-2. He could have been playing tennis pleasantly, but she could have unpleasantly. ( )

?4-3. He could have been playing tennis pleasantly, but she could have been unpleasantly. ( )

(i intended to say "He could have been playing tennis pleasantly, but she could have been playing

tennis unpleasantly)

Coordination Test

5-1. Frank could have been washing and ironing his shirts yesterday. ( )

5-2. Frank could have been washing and been ironing his shirts yesterday. ( )

5-3. Frank could have been washing and have been ironing his shirts yesterday. ( )

Though Movement Test

6-1. Playing tennis a lot though he must have been, he doesn't look tired. ( )

6-2. Been playing tennis a lot though he must have , he doesn't look tired. ( )

6-3. Have been playing tennis a lot though he must have, he doesn't look tired. ( )