- What is the minimum size tribe that should be allowed to control a territory? I think BAND is good to start off with.

Agreed. I think band size could even always be the right minimum.

- How many control totems should be required to claim a territory? I think 4 is a good starting point, possibly 2 or 3 though due to the currently low population.

I propose a minimum of 1, with requirements and drawbacks to establishing more. Say two tribes compete for a territory and each hold one totem; they could either capture the other tribe's totem to monopolize the territory, or place a third totem to hold a territorial majority of two totems versus their opponent's one. (Territory ownership could be determined by whoever holds a majority of totems in that territory.) Their opponent could then establish their own second totem to contest ownership of the territory. A contested territory could be lawless, with open PvP, until resolved.
Totems could have scaling upkeep requirements, so that more totems are more difficult to maintain. A vast empire would therefore have difficulty maintaining its sovereignty when faced with numerous local tribes, providing a better opportunity for rising tribes to carve out territories of their own. (Perhaps territory laws, such whether PvP exists, could be established by a voting system, whereby multiple bands could essentially share territorial ownership, each totem controlled giving them one vote). This means competing tribes could stake out more totems in order to gain a majority in a territory, but if they can't support those totems' upkeep, then they have doomed themselves to lose control of that territory.

Summary: Territorial laws could be established through votes. Each totem controlled would give a band one vote. Majority rules.

- How much land should a control totem claim?

- How often should control totems become ‘open’?

Once per week, per territory.

- For how long should control totems become ‘open’?

One hour. This is enough time for concentrated battle plans to unfold.

- Should control totem’s alternate being open, or should all of them be open at one time?

Territories could alternate semi-randomly, with preferred times being whenever the online population peak is for that territory. Therefore a territory could be controlled by a Polish tribe, with PvP running during their own peak hours.
Sometimes two totems could be contested at the same time on the same day, sometimes more. Alternating would allow larger, active, and powerful clans to spread across territory throughout the week, while not needing to defend their captured territory until the next week comes. We might even see roving warbands this way, who don't bother to establish totem defenses, and leave ruins in their wake.

- Would you like to see the controlling tribe set a territory to Safe or PvP? Or would you like to see controlled territories always be set to PvP? (Regardless, while control totems are open the entire territory would be open to PvP)

Absolutely. This would be a great way to bind PvP and PvE servers together. It would be fascinating to see some territories holding a peaceful balance, while others are in constant chaos. Territories could remain safe by establishing numerous totems and using the voting mechanic I outlined earlier.