How long have Focus Group and Neighbour Group people been in contact overall?

Presumably from about 3000 BP.

Hypothetical of course, and this depends on assumptions about the identity of Eyak and Riverine Kachemak (cf. Davis 1996, Workman and Workman 2010)

What is the overall time frame when the largest number of people had the most opportunities for interaction?

ca. 3000-1500 BP

How long have Focus Group people and Neighbour Group people worked together for?

Unclear, but probably over an extended period of time; evidence of shared and typologically unusual grammatical features (cf. Leer 1991, Berge 2016, 2018); probably in period between 3000-800 BP (neighboring contact up to about 1500 BP, more remote contact after arrival of Alutiiq, who would have created a wedge between the two groups. The Eyak were riverine inland people, and new to their historical homeland from around 1200 BP; but prior to that, there are some archaeological connections between Yakutat (one of Eyak settlements post-1200 BP) and Riverine Kachemak of northern Kenai Peninsula (cf. Davis 1996). Aleut may have been main Kachemak in currently Alutiiq areas (cf. Berge forthcoming, Dumond 2001, Maschner 2016)

What is the time frame when the largest number of people had the most opportunities for interaction in the labour domain?

cf. above: slavery existed for at least 2000-3000 years along Pacific Coast, and the most direct and intense contact would have occurred prior to 800 BP

How long have Focus Group and Neighbour Group people been in contact in the local community?

Archaeological evidence for the interaction of different Kachemak groups (Riverine, which may have moved to what was the Eyak homeland ca. 1500-1200 BP, cf. Davis 1996, and main Kachemak, which was associated with Kodiak and which may have been Aleut, cf. Maschner 2016, Dumond 2001, Berge forthcoming). Thus there was presumed extended contact between around 3000-1500 BP; and lesser and more indirect contact via slavery and long-distance trade after this time

What is the time frame when the largest number of people had the most opportunities for interaction in the local community?

Again, prior to 1500 BP there would have been more regular and intensive contact, but the institution of slavery may have had much to do with subsequent interaction in the local community

How long have Focus Group and Neighbour Group people traded for?

Trade between the Aleut and the Eyak likely occurred over an extended period, presumably over 1000 years, if the period of direct contact was prior to 1500 BP, and there was enough contact for shared linguistic features, and less direct trade continued after the arrival of the intervening Alutiiq Eskimos...

What is the time frame when the largest number of people had the most opportunities for interaction in trade?

prior to 1500 BP, any time between 3000-1500 BP.

This is based on the archaeology.