Marimaia wrote:(...) I know that Valendia has Brunei as a colony and that it lies well within the region I'm concerned with. If they colonised it before the Margraves arrived in Asia then they'd be part of the scenery by then, or they might do a deal with the alliance where both sides leave each other alone (I shall check with Europe-Prussia). (...)
Valendia conquered the Sultanate of Brunei (though considering the lack of powerful Islamic states on the Arabian peninsula capable of expanding Islam through SE Asia I suppose it would be the Kingdom of Brunei) in the 1500's, so they are veeery well established by the time the Margraves had the thought of forming Marimaia. The empire wouldn't have cared of Marimaia's expansion into Borneo, but if they tried the same tricks that they used on the Philippines on the Valendians or had tried to harass the population then the empire would have retaliated, quite brutally in fact.
There's also the slavery part to consider: by the 1800's slavery was forbidden on the empire, so if by then the slave trade was still strong, while Valendia wouldn't have declared war, they would have financed pirates and corsairs to disrupt the trade in every way possible.
There's another option however: if the lack of continuity on the map bothers you so much, I'm not opposed to give up Brunei and claim another piece of land instead, provided there's no objections from the others, and there's a territory in SE Asia with similar characteristics to Brunei (position and natural resources).