Yes split the declaration.

But note that the $800 exemption can be used just once every 30 days, and it is not cumulative during those 30 days.

So if you know you'll be traveling again in 30 days, and at that time will be bringing back more than $200 of stuff (or more than 50 cigarettes, 10 cigars, or 5 oz of alcohol or perfume), then you would be better off splitting it as $900 for the wife, and $200 for you. She then uses the $800 personal exemption, and is subject to duty on the excess $100 (which will almost surely be waived), and you use your personal $200 exemption.

But the $200 exemption is usable only if you've been away 48 hours or more. If you've been out less than 48 hours, then put all $1100 on the wife. With $300 over her exemption, it is somewhat more likely she'll pay duty, but even so it is pretty cheap ... $27 in this case.

It is pretty complicated (and I haven't even gotten to the $1600 exemption which is pretty mind boggling). Non-GE frequent travelers pretty much ignore this, and I suspect routinely mistakenly use their $800 exemption multiple times in 30 days (and the amounts are likely too petty for CBP to pursue). As a GE traveler the bar is much higher for you. Adhere to the rules 100% in order to keep your privilege, and I suspect you'll live the same pre-GE duty-free existence you had before. The CBP wants compliance more than it wants a few dollars out of you. Maintain a spreadsheet if you have to.

Note that origin of manufacture can result in exemption of duty. E.g. stuff made in Mexico and Canada is exempt.

Remember to bring cash in case the duty station doesn't accept Visa or MC. $100 cash is plenty for most situations.

Since everyone isn't GE, no. If there is a separate GE line, I suspect a hassle if the GE holder uses the non-GE line and hands the GE receipt to the CBP officer. The GE program appears to be intended for people who can navigate an airport independently, hence the bar being set at age 14 and higher.