Let me take a kick at how this could work. I'll number my thoughts for easy reference.
1. Canada is already the battlegroup leading nation and needs to fill an additional slot as the brigade group headquarters. The most difficult job they will have is developing a CSS structure that will work for a multinational brigade, within a multinational division context, facing high intensity combat and to get away from the NSE concept of all singing all dancing support. Step one is to throw out everything regarding logistics that Canada has done sine 2000 and all the bad lessons learned in Afghanistan and to dust off the cold war logistics doctrine while appointing the smartest guy in the logistics branch to oversee tall of this.
2. Canada needs to lock up the regimental cap badge mafias and structure itself to properly sustain the brigade indefinitely.
3. The most efficient brigade structure (considering its multinational nature) is one of an Armoured BCT using combined arms battalions. The multinational nature makes regroupings on the fly difficult and therefore as much as possible each combined arms battalion should have all the necessary armour, infantry and anti-armour it should need. My own view is that two battalions should tilt infantry heavy (because we are primarily defenders) but one should tilt tank heavy.
4. Canada should form one complete combined arms battalion consisting of one squadron of a squadron of Leo2A4M and two companies of LAV6. There also needs to be a battalion headquarters, a combat support company with recce and mortars and a combat service support company. Of these, the battalion HQ, one rifle company, one tank troop and one half of the combat service support company should be a rotational forward deployed element as it is now. The rest of the battalion's equipment will be propositioned in Latvia while the troops remain as rapid reinforcements in Canada but attend on regular exercise schedules which concurrently exercise the RCAF on the deployment plan.
5. Two additional combined arms battalions are required. Each of Italy and Spain already provide fairly large contingents of a rotational predeployed mech company supported by a half company of tanks. They should be persuaded to double their force through a similar prepositioning of equipment with a rapid redeployment manning.
6. Artillery may be an easy issue. Latvia has enough M109s for two battalions but only one mechanized brigade. It should be convinced to put one of those battalions in direct support of the new multinational brigade.
7. Brigade recce/cavalry is required. Poland already commits a company of tanks and Slovenia a recce platoon. Slovakia has a mechanized company. Between these three nations their commitments could be restructured into a cavalry battalion.
8. Engineers are problematic in that there are only two small platoons there. One should have an engineer battalion with at least two companies. This is a role where perhaps Canada should put another hundred personnel forward deployed and a further one hundred as rapid reaction to form the core to which the two multinational platoons can be joined.
9. The Danes have also recently brought a fairly large contingent in. I'm not sure where they are although indications are they might be with the Latvian Mechanized brigade and as such their availability to the Canadian -led multinational brigade is probably zero.
10. As far as a brigade headquarters is concerned, I'm of the view that this should be a three year posting for the key staff - say around 50. This becomes a major commitment and should not be subject to the usual rotational turbulence. On top of that the brigade staffs in Canada need to be kept intact to continue to run their own brigades. 50 is not a large number and if we can't find 50 decent staff officers and NCOs within the Army then we're not trying hard enough. The remainder of the brigade HQ is primarily signals which do not need a large deployed forward presence but can be filled as rapid reinforcement elements.
11. Now we get to the hardest part. Logistics. As a starter, because of the diversity of equipment, each battalion sized element needs its own robust first line of support, especially for maintenance while supply and transport can be partially rapid reinforcement. The same is true for second line support at the brigade service battalion. Maintenance is a challenge and needs very detailed analysis and a very detailed organizational structure that can work forward with the national contingents and backward to the national theatre sustainment agencies. Supply also needs some tight control and a forward deployed presence while transportation services can be more generic and largely dependent on rapid reinforcement troops so long as the predeployed equipment handling capabilities are capable of multinational cargo handling. Again, IMHO this is one of those places where we should seriously think of making it a three-year posting for roughly 50 key personnel while another 100-150 or so could be rotational predeployment and the remainder - say 4-500 could be multinational rapid reinforcement troops. I'll leave aside the question of how the brigade ties into the multinational division's logistics plan/system because, quite frankly, I have no idea how well developed that system is.
12. I would think that the rapid reinforcement personnel would not be required often. I would think two very short exercises a year aimed at fly-in reinforcement, deployment to a an assembly area followed by redeployment, equipment maintenance and return home. In addition at least one major exercise per year of three to four weeks duration to test the deployment and to exercise the battalions and the brigade in full. The three combined arms battalions could conduct further independent battalion exercises as part of the reinforcement exercises.
13. As for Canada, I see the realignment of the three domestic brigades so that 1 CMBG has one armoured and three mechanized battalions whose responsibility is as the primary provider of the combined arms battalion headquarters and the two rifle and one tank company. With nine rifle companies and three tank squadrons it should not be difficult to generate one full time rifle company and one tank platoon for rotational forward deployment. More difficult will be the battalion headquarters and the rotational maintainers. Consideration should be given to having the key battalion command and maintainer positions to also be three year postings - say 50 PYs. As for 2 and 5 CMBG, my view is 2 needs to become light and rapid reaction and Northern oriented while 5 becomes fully mechanized as a medium multipurpose force.
It's clear to me that one cannot keep a commitment like a brigade in Latvia based solely on rotational elements. There are continuity issues that require a full-time long term posted-in element, other positions that provide a rotational full-time presence and yet others that can easily be filled by rapid reinforcement troops that are designated for the task, trained for it and DAGed ready to go as part of a Joint Fly-over plan. All of that works best if concentrated in one brigade with as little as possible scattered around the country.
My $0.02 (I'll probably throw in an extra penny or two later)