Well first of all there is something that is very important here, I think it is not useful to compare doubles with long runs, as you don´t have the availability for long runs anyways. It´s like comparing training in Swiss vs training in the Netherlands for long mountain ultras. If you can not do long runs, then there is no need to regret not doing some.
Now the question that is more relevant here is how to build endurance and fatigue resistance without using long runs.
On that subject I´d say that first of all, you have a very strong base as it seems that you´ve been running a lot for quite some time, so you have all those accumulated miles in your legs and that should help you a lot.
Also, you´re talking about 140km weeks. As mentioned before that is A LOT, especially if you don´t have a lot of availability for recovery. You might consider doing a little less as you might be overtraining, not to the point that you hurt yourself, but to the point that you don´t make as much progress as you could with more recovery.
On the subject of doubles, I´d say that long runs are mainly useful to learn how to run on tired legs, but you can very easily do that with doubles. Especially by doing once a week a hard workout with threshold/tempo or else in the morning, and then a mid-long (1h30/2h) run in the evening.
You´re training for 100k which will probably take you most part of a day (if not all day) to run, with long breaks at aid stations. So one important aspect is just to be on your feet all day. Running in the morning, then taking care of the kids and running around the house all day, and then running again in the evening is a fabulous training! 😉
You´re also talking about doing doubles everyday with an hour each. If I were you I´d try to change that a bit, with most days only one or zero running, taking care of the family at home, so you can free some times for 2 days in the week when you can go longer/harder and do doubles. Basically the old principle of keeping the easy day easy and the hard days hard, instead of moderate training everyday.
Muscular endurance workout is a great way to build the resistance that you would get on long runs, and you can do that at home while watching the kids, so don´t hesitate to incorporate it into your training, even if it means you do that instead of a run!
Finally, the all-day adventure, with all that accumulated fitness and high mileage weeks should be more than enough to help you prepare for the race. 1 all day adventure every 3-5 weeks for the 12-weeks leading up to the race should help you a lot and make up for the super long runs that you haven´t done.
But really, don´t forget to rest, because that is when you assimilate the training. 😉
PS : English is not my mother tongue so forgive me if I made some mistakes, or if I´m not clear on something, don´t hesitate to ask me to reformulate !