Wow that's somewhat similar to my story when I first went to Africa in 2014. I was a few years younger and more of a time budget issue. But I had been busy building my businesses and hadn't hunted big game in about 30 years.
One piece of advice, you probably won't take it but... Get great pictures, even consider a professional video. But don't do taxidermy. If you do want taxidermy, consider if you want to enter anything in a record book. If not, how about putting all trophies under one name? One shipping crate. One bill for permits, one clearing bill, etc.
Now I do recommend you and your brother in law hunt separately with seperate PH's. Especially if you want the same critters. However you will likely average 1.5 to 2 critters per day. You'll have a day with 3, and a day with nothing

So do some math on days and animals. If you are booking more days than you want trophies to pay for.... And you want the most experience per dollar, consider hunting together with one PH. You get to participate woth your buddies excitement. But for sure agree ahead of time as per which critters you will each shoot. At all cost don't set up a situation where bad feelings develop.
There is only one first time. Very easy to go a bit nuts

Especially if you make it back many times. (I've been on 10 Africa Hunts so far, hopefully many more to go). You will inevitably have critters mounted that in the future you may wish you hadn't... Unless you are someone who really holds Taxidermy in high esteem. If you forgo doing Taxidermy, or even do a limited number of critters and ship with someone else's, you can hunt almost double. Even if you were to do European Mounts, think about rather just have skulls cleaned and bleached. Get them home and mount to a piece of wood yourself. Or buy some Skullhooker products. You can do this for about half cost of European mounts.
And ask yourself and your wife where you will put Taxidermy.