Had it with my reef tank

Hello all,
I am new here and as you can see from the title of my post I am ill with my
reef tank. I have a 75 gal reef set up that I could never get the handle on
and set up right. This has been going on for about 3 years. Before then I
had always been in freshwater (7 years). Thinking of coming back and
throwing up my hands with my reef which means I will be getting rid of a lot
of stuff. I plan to start a planted tank for which I enjoyed very much
before and was definitely less maintenance than my reef set up. My questions
a

1) Can I use my wet/dry trickle filter plus a magnum 350 canister filter and
that's all? Before I used a undergravel filter as well.

2) I still have my gravel left over from years ago. If I rinse it well can I
still use it. It is natural pea gravel. and how thick should I make the
layer in a 75? I had a 55 gal before.

3) I have a power compact unit for lighting. Will that do for plants or will
I need to supplement it with an additional light?

4) It has been so long, How long will it take to cycle a 75? Can I cycle
with plants or do I need to add them gradually?

5) I have 4 powerheads. Are they useful in a planted tank? I can hook air to
them to aerate the water.

6) I have had cichlids in the past and angels. What would be the limit
number or inch of fish in a 75? Or does it determine on how many plants you
have?

7) Sorry, this may be a stupid question because it has been so long since
freshwater. Do I siphon the gravel with a planted tank or leave it alone
when I do water changes.

8) I have a RO/DI unit for filtering water. Will it be useful for
freshwater?

I am sorry this is so many questions and I am sure there will be more. Just
trying to determine if I want to make the switch or not. I even thought of
getting brackish fish but not sure what plants would tolerate salt of course
in low concentrations, not at a marine level.

Hope someone can help me or at least point me in the right direction. Maybe
someone else has gone through the same thing that I am thinking of doing.

I am sure many changes and techniques have changed since I was in
freshwater.

Any suggestions would greatly be appreciated.

Thank you,
Paulette