2) Build feature into trail cameras (cell or preferably not) that can be set to activate at a later date. Would love to get my cams out now while scouting but save the batteries I really don't need or want the photos until months from now in mid summer.
You can make batteries last a long time if your camera isn't taking any pics.
I do something like this with my Spypoint cameras. During off-season, I turn off my paid subs and just go with the freebie plan (250 pics per camera/month....with their Insiders membership, 100 otherwise). Then I turn down the sensitivity and increase the delay between photos, to minimize the number of pics taken. Their phone app lets you adjust these parameters remotely at any time, which for cameras that might be remote and harder/longer to get to, is a real convenience. A few of my cameras get placed deep in the back woods in early Sept, well in advance of the late October moose hunt. That's almost 2 hours drive away, plus another hour in by ATV, one way....so being able to place them early and then control the parameters and have the batteries last till the hunt almost 2 months later is huge for me.
I also use rechargeable lithium batteries with all my Spypoint cameras (5 so far). They last a lot longer than AAs, and are cheaper in the long run, though the up front cost is a lot higher of course.
One of my minis has a solar panel built in.....with the Li battery, that has been out on my property for months now and still shows 100% battery! If you position such a camera where it can get some direct sunshine (hole in the canopy above), then when you minimize the # of pics, the battery will almost last forever.
I have two of the newer Flex models....great features and resolution.....they are coming out with an integrated Li/Solar model this summer, which will be perfect for long term and/or off season use and I plan to get one before the Fall season. I'll report on my experiences with that model when I get my hands on one.
Other brands of trailcams may have similar features, though I can't comment on that since I don't have any of those.
Given that cellcams are getting cheaper/better, I think the extra cost of having cell over non-cell ones makes sense. YMMV