So how does this work exactly?
If I don't pledge my membership then will it be refunded in full even though I have been to one home game already and have received my merchandise? Or would they do a partial refund?
If you want / need a refund you'll probably have to email the club about that. I believe if you don't pledge nor ask for a refund, the club will assume you're ok with letting them keep your money.
What happens if things improve to the point where we can attend games at Lottoland this season?
You'll get to see a few mighty Manly wins.
If I have pledged my membership do i get to attend using my membership that I have pledged
Yes
and if I have not pledged then would I have to buy another membership or else buy entry to the game?
No, assuming you haven't been given any refunds, your membership remains 'in play.'
And how will membership numbers work this year?
Still using the laws of basic addition (lol). cough
If I don't pledge then will I not be counted as a member this year
Unless you've received a refund, you will be counted as a member.
and hence will be removed from the membership number tally?
No, because... unless you received a refund, you have still paid to be a member, pledge or no pledge.
as @SeaEagleRock8 said, it gives the club an idea on how many people don't want a refund. Also, "pledgers" seem to be getting a certificate and possible some other benefits next year.
This is my take on it.