As others have stated, those up-grade prices are way out of line.
Next time you contact the dealer you might casually mention that you have researched costs on the Forum.
Not clear on those start-up costs, (Pre-delivery Inspection?), It's not a Moon Launch after all. Just what is he starting-up?
$1000 for a Fantastic fan is absurd, especially if the vent is already there.
IMHO The generator would be a much better alternative, to the inverter. Add an extra battery and you have a lot more versatility.
Have them test the batteries, they could very likely need replacement, ( I would insist on replacement before taking delivery, ck the tags for dates)
Solar, I got a 30w portable system on-line two years ago for $1000.00, pretty basic but it serves our needs just fine.
When you pick your "baby" up pay special attention to the walk through, should take at least 2hrs, 1hr the first day and 1 more hr. after breakfast
when you wake up on his lot the next morning....for real!!! TAKE NOTES. ASK QUESTIONS.
We were all newbies at one time, the idea is to be a Smart Newbie.