I call BS on this estimate, this shop is doing what many shops do, they price out every job then add it up, even if there are overlapping labor operations. This is how many shops "stick it to the customer".
What they will claim is since it is an estimate, they do not know what the customer will do, so this is why they price out each repair separately.
For example, if you change the oil pan gasket, you are changing the oil by default, the only other operation is changing the filter. A real shop will do this gratis as you are already spending a lot of money on a much more sizable repair anyway. If you have your oilpan gasket replaced, would suggest you sort out the oil drain plug, Helicoil is the way to go, the best solution is have the outside of the oil pan recess welded up to increase the thickness, machine the outside hump flat, then Helicoil the oil pan, you should never have problems once the oil pan is addressed this way!
2nd problem I see with redundant labor operations is the transmission mount and the shifter bushing. If you change the transmission mount, the shifter bushing can easily be changed while under there, the rear (more expensive bushing does list for around $70, but takes about 5 minutes to replace once you are under the car. The front carrier shifter bushings are very cheap and really should be replaced as well, if you have the trans cross member down, pop the rear carrier bushing, then the front bushings can be changed quickly, BUT this means the shifter needs be removed, which would take more time. Unless they are quoting the shifter bushing at the base of the shifter, which is a different matter and most likely will not need to be changed anyway.
I see mention of the Guibo as well. Note that there is a small centering bushing inside the Guibo that is VERY important to replace when working on the Guibo, If there are vibrations, also check out the driveshaft center bearing a buytl tape as well.
The windshield gasket I assume is the outer rubber molding? Not an issue of water leakage, this is really a DIY job if you are careful to remove the old piece, if not, get your own parts and take it to a glass shop, it will be quicker and cheaper than this outfit.
Look carefully at the estimate as well, SL = Sublet, ie this shop is not doing the work, or they have a different department doing the work.
Sublet = markup = more profit! Shop these items yourself and save some money and/or DIY.
Good luck.