I'm by no means an expert on Scottish football but I've been reading a lot about this and I consider myself fairly clued into how the money works in all this stuff, and how the various fans feel. Some of these answers seem fairly predictable if you have been reading the right sources. Here's my take:
It will be interesting to see how this pans out, if rangers are dropped into the third division, will they still get 45,000+ every week?
They won't get 45k but they won't be a shambles. I've been reading a few Rangers blogs and articles and overwhelmingly their fans want to go into D3. In fact they may lose fans if they are allowed into D1 or the SPL. This is probably mostly attributable to a sense of "well we're not going to go bust so let's see how long you last without us". If they are put into D3 they inflict the maximum punishment on everyone else and their sense of injustice will be sated. If they make other clubs go bust they will be more the happier - they know there's plenty of cannon fodder to promote from the Highland League if clubs genuinely fold and can't even Newco like they did.
How long will it take them to get back to the top division?
About as many seasons as they are divisions off the top. The world will be cheering the little teams on praying for the odd David v Goliath victory, but honestly, they will power their way through the leagues.
It's not to say Rangers won't come out weaker from this. It's just that no club in the SFL can hold a stick to Rangers, even a dismantled, re-founded Rangers.
How will Celtic fare without their yang?
What sense of loss of tradition or Old Firm culture they feel will more than be mitigated by the fact that the SPL and SFL will basically engrave their names on every trophy they put up for competition. I'm sure that they would compare their feeling of "lack of achievement" at winning the SPL at a canter as about comparable to our "lack of achievement" because we didn't win the Premier League "the right way". That is to say, they won't care.
When Rangers get back into the top division, will their fans go to away games against the clubs that voted to relegate them?
A genuinely interesting question. Probably depends on whether they go into D3 or D1. If D3, I suspect they will consider their revenge complete based on the financial hardships they will have imposed.
How many of the other clubs will survive without the crowds that attend when Rangers visit?
Another genuinely interesting question.
Will sponsorship revenue drop?
Undoubtedly. Those clubs that have a long sponsorship deal which will survive 'til Rangers resurface in the top division have essentially dodged the bullet without even meaning to.
Will people start to go and watch their local clubs instead of travelling from all over Scotland and Ireland to either Parkhead or Ibrox?
No. They will keep following Rangers in the lower tiers for the same reasons we kept attending in the third tier, or keeping following Celtic as they get a glorious chance to re-write the record books on consecutive wins, or stop going to matches entirely.
You might have read some blogs but I suspect you misjudge a lot of the Rangers support. Their support in the past has been somewhat fickle to say the least.
I am not at all sure that other clubs will have a lot of problems without Rangers,the home gate receipts may well go up as a force that has been seen to be corrupt is removed.
Ibrox has a lot of fixed costs without an SPL income it is by no means sure that they will be able to service both those costs and the contracts of players already there.
No one knows what funds are available to McCoist, Newco could well go into administration very rapidly.