I would just call in to Amex and ask about statement credit , they told me when i asked before that it would automatically be picked up. My american airlines taxes when i changed my flight last week are supposed to be picked up but i had already picked aa as my airline for statement credit. As far as hotel and car rental goes you can use amextravel.com to use your MR points to book hotels and the such, but it would not be an real good way to use your MR but you can still do it.
@takeshi74 wrote:No idea on point cost. It depends on redemption method and that's something you should have considered before applying as redemption method will impact reward value. Generally, transferring offers best value so see what it would take with MR's hotel partners. I don't recall if there are car rental partners or not. As stated above, you can use the travel portal but vlau eis generally not as good. Gift cards may also be a possibility but they will also generally offer less value. Yet another option would be a credit for a chage but that's probably the worst use of MR points in terms of value.
As for the airline fee credit, you have to select the airline first. Your research should have covered this as well. See also the Flyertalk thread on the airline you intend to select.
@icyhot wrote:
I also have a friend coming with me and we're splitting the cost, what would be a reasonable amount to ask for her share for with MR?I'd look at the dollar cost for the items for a comparison. Again, this should be part of your rewards value redemption considerations with programs like MR, UR, TY, etc prior to applying.
Why do so many of your replies suggest the original poster (not just here but all over) should have thought before they applied? And then imply they should not have applied, when that app has already been completed?
The poster is trying to make sure they understand the best redemption option, a legitimate question to ask. Either provide constructive suggestions in that topic, or don't reply if you have nothing constructive to add.
@NRB525 wrote:
@takeshi74 wrote:No idea on point cost. It depends on redemption method and that's something you should have considered before applying as redemption method will impact reward value. Generally, transferring offers best value so see what it would take with MR's hotel partners. I don't recall if there are car rental partners or not. As stated above, you can use the travel portal but vlau eis generally not as good. Gift cards may also be a possibility but they will also generally offer less value. Yet another option would be a credit for a chage but that's probably the worst use of MR points in terms of value.
As for the airline fee credit, you have to select the airline first. Your research should have covered this as well. See also the Flyertalk thread on the airline you intend to select.
@icyhot wrote:
I also have a friend coming with me and we're splitting the cost, what would be a reasonable amount to ask for her share for with MR?I'd look at the dollar cost for the items for a comparison. Again, this should be part of your rewards value redemption considerations with programs like MR, UR, TY, etc prior to applying.
Why do so many of your replies suggest the original poster (not just here but all over) should have thought before they applied? And then imply they should not have applied, when that app has already been completed?
The poster is trying to make sure they understand the best redemption option, a legitimate question to ask. Either provide constructive suggestions in that topic, or don't reply if you have nothing constructive to add.
+1
There seems to be quite a bit of this lately... folks don't come here for judgement, they come here for help and/or answers.
If one doesn't have something constructive and/or helpful to add to a thread, one really should refrain from posting.
Back to the topic, I would select Delta as your preferred airline ASAP (if you haven't already), and if the Delta incidental doesn't get credited automatically it's likely Amex will manually adjust it (even if they don't, since it's a small dollar amount it's not a huge loss, and you'll be set for future incidental credits).
In the past when I traveled with someone and points were involved, I would simply check the cash price of the ticket/hotel/etc. and use that as a basis for coming up with how much I was owed by the other person. The couple of times I've done this I've made sure the other person got a 'really good' deal as well (I didn't ask for an entire 'half' of the cash price) so when everything was said and done we were both happy. 
I know the OP had other concerns as well, but this is the extent to which I'm qualified to speak; some others have had some great suggestions, and I'm sure even more will follow.