#3
simplest thing would be stay in an F major, or a D minor scale
#4
Those chords are diatonically all in Dminor/F Major (and yes its a Bb) - so if it wants to end on a Dm use D minor or D minor pent, if it wants to end on an F use F Major or F Maj pent.
#7
f maj scale, but cob tend to like to travel on arpeggios, so swap from f being the root to Dm being the root of arpeggios and you'll be good
#8
Play the notes used in chords?
I live near Lake Bodom WORSHIP MEEEEEEE

Quote by Sami Philadelph
LOL, for some reason the impression I get from you is like some wacky Frank Zappa of metal pulling pranks at the Grammys and telling crude jokes during interviews.
#9
Your mad shredding skills are certainly for a good use when you can't see that those chords are in D minor. Honestly your not gonna impress anyone by asking a forum how to write a solo for your song.
Quote by thsrayas
Why did women get multiple orgasms instead of men? I want a river of semen flowing out of my room to mark my territory.

You can play a shoestring if you're sincere
- John Coltrane
#10
Quote by SynNeverHurts

What the heck? E#? F major has a flat: Bb. No sharps.
“Baaaaabe,baaaaabe,baaaabe....”
~ Robert plant on being asked what his favorite food was

“Baaaaabe,baaaaabe,baaaabe....”
~ Robert Plant at his Grammy acceptance speech

“Baaaaabe,baaaaabe,baaaabe....”
~ Robert Plant all the time
#11
Quote by guitar*guy
What the heck? E#? F major has a flat: Bb. No sharps.

That is F# major.
Quote by thsrayas
Why did women get multiple orgasms instead of men? I want a river of semen flowing out of my room to mark my territory.

You can play a shoestring if you're sincere
- John Coltrane