I've never been to Mt. Siskiwit but it looks like a moderate dayhike from W.CB, even though u will be climbing approx 53 stories to get there. From the map it looks like u have to scamper a bit off the ridge trail to "summit" Siskiwit, and perhaps others can comment whether the view is open in all directions, as there is no tower to climb. I think it would be neat to look down on and across Siskiwit Lake, as well as Superior to both sides.
The Ojibway tower would be a 15 mi roundtrip, really too long for a dayhike, even with a light dayback- at least that's what i figure. Just as important, there is no access to drinking water for nearly the entire route along the greenstone ridge, so u'd have to carry a ton of water.
Unless u are a glutton for punishment and by that i mean physical pain, Richie Canoe & Whittlesey require a canoe, kayak or jetpack (NPS frowns on the latter). There are easier and better ways to achieve isolation on your route, such as:
Leaving the Lake Richie Trail and heading toward Chippewa H. on the indian portage trail, u will notice that the "indian trail" is laid out away from Richie, providing lots of opportunities to bushwack into the lake shoreline. Towards the end of the first mile, u will cross a stream. Dont try to hike in using the stream as your path-it will likely be overgrown and impassable. Instead, hike 50-75 yards or more beyond the stream, and THEN leave the trail to bushwack to the lake, heading due west using your compass. (Its a good idea to bring a backup compass, in case u lose or break one; even a cheapie compass is invaluable at isle royale). That shoreline and the south "arm" of Richie get the lightest fishing pressure (Richie is very popular for northern pike fishing and has produced large specimens over the years). Buy your son a 4-piece fishing pole for $22-28. (2-piece rod will get hung up while backpacking, and there's no greater disaapointment than to be in the park and your fishing gear is kaput).
Once u are at the shoreline, u can mosey right or left along the shore and explore/fish. To return u dont have to retrace your steps, but instead be sure to head due east to get back to the trail; otherwise, u can end up going a long way without hitting the trail. If u head due east, might u end up with a longer overall trek back to the trail? Yes, but dont risk it, as its no big deal to have to walk an extra 1/4-1/2 mile on the park trail compared to bushwacking that extra distance. Uncertainty can lead to confusion, which can lead to panic, which will likely result in poor decision-making ... .
U cannot get to whittlesey on foot without fording a pretty deep stream, at least navel deep if not deeper, but that would be one of the slightest obstacles involved. Not sure what map u are using to pose these various options in planning your trip, but either it does not have sufficient detail, or u just dont have a genuine appreciation/ understanding for hiking off-trail on the island, which is understandable, given u havent been there yet.
I believe that the moose would prefer not to "run into" us on the island. The fact that they nevertheless routinely travel on the park trails is perhaps the best testament to the formidable challenge posed by off-trail travel. When u do see one, be sure to ask him/her how easy it is to find a flat spot to lay down or to set up even a pup-tent for cross-country camping! You will know what i'm talking about when u see the individual tent sites at Richie, which were identified/cleared with some forethought and planning (presumably).
It's not a bad thing to "push the envelope" in formulating your trip plans, as u r generating a good discussion about what is realistic and also safe. There are no medical facilities in the park, and backpackers are on their own, for the most part. Help can be a ways off, even when u are staying at an outpost, so keep safety at the forefront of your planning. Hypothermia is one of the biggest concerns while in the park. Lake Superior is more like a sea, in that it is capable of producing its own weather, and a rainstorm can drop buckets on you with the wind forcing the rain sideways-u then either wish 1 of 2 things: 1) u were home; or 2) u were a turtle. The island has incredible rewards, but there are significant identifiable risks as well. Don't underestimate them. Of course, I have to say the rewards are well worth it.
I understand what you are saying about Daisy farm, is there anywhere else along Moskey to explore while we are there for two days? I've kinda thrown the backcountry camping out of my mind...for the sake of my travlers anyway 
But I wouldn't mind a backcountry hike...would it be a bad idea to follow that stream on the south side of Moskey?
