#1 - yes it is possible, one spouse can give the other spouse the down payment, it'd be documented as a gift (so you should talk to your tax advisor about any gift tax implications)
#2 - whether you are buying in California or Nevada, even if the non-borrowing spouse is not on the purchase agreement, they are fine to be added to title upon the loan closing. Your lender & the escrow company both need to be aware that is what you want to do or they will not draw up the closing documents correctly.
#3 - relates to my answer to your first question, yes it's possible as long as your wife can qualify on her own.
However if you are planning on financing over $625,500 on a 1-unit property you need to get your plan together ASAP, as the conforming loan limits* in San Mateo County are dropping from $729,750 down to $625,500 here at the end of September - so if you are aiming at using conforming financing you need to have closed on your home by then if you want to talk advantage of conforming loan programs & their interest rates. Otherwise everything over the $625,500 loan limit will be non-conforming, or straight "jumbo" loan programs, which have slightly different credit requirements and not as as attractive rates (not a ton higher, but but not as low).
* The conforming loan limits are $417,000 across the U.S., but in high cost areas the conforming loan limit exceeds that amount, all the way up to $729,750 in the highest cost areas of the U.S, per the Economic Stimulus Act in 2008. However it is currently scheduled that the end of the fiscal year (September 30th) will mark a reduction in those limits to no higher than $625,500 in the highest cost areas.
If you need help figuring anything out, have more questions, or need more information feel free to ask and I'd be happy to help.