Good painting noigrim. I find I no longer have the vision or the stamina to paint up masses of 15mm figures, though I keep working on a battalion here and there from my back inventory. None of my projects is ever completely done, but I'm not starting any new ones in 15mm.
I don't see that anyone answered your question about light infantry.
British light infantry companies were administratively part of the regiments of foot, one light company per battalion. Light companies were converged into light battalions for field service, with battalion organization usually remaining stable through a campaign or even longer. Light battalions were often grouped, along with available converged grenadier battalions, into one or more 'elite' brigades per army. There were seldom enough regular lights to form a brigade by themselves.
The Continental army went through several organizational changes. Washington formed an experimental light infantry 'corps' of chosen men in 1777. Congress authorized one light infantry company per battalion in the 1778 organization, and this was kept in the 1781 organization. Similar to the British system, light infantry companies were converged into light battalions. In Washington's Main Army, the light battalions were grouped into Lafayette's Corps of Light Infantry, a division of 2,000 men that was the flower of the army.
German regiments had no organic light infantry. A few companies of jaeger were sent to North America, armed with a mix of muskets and rifles.
I believe the French at this time had one Piquet company per infantry battalion, which were converged into light battalions.
I don't know about the Spanish, but doubt they had light companies in their infantry regiments.
However, in North America, the regular light infantry was the least of it, as both Patriot and British/Loyalist armies fielded several regular Legions and Partisan Corps for the petit guerre, and both sides fielded large numbers of Indians and white rangers as irregular light infantry. Regular light infantry were kept with the main armies and used mostly as shock troops, rather than as scouts and skirmishers.