As far as I know, to the time of the spanish-american war, the british influence and presence was well established in Sabah. The sultans of Sulu (and Brunei) kept the claim alive but Spain, after early protests to the british, relinquished their support to the Sulu sultans in the matter in order to keep good relations with the british. If I'm not wrong, was the USA who revived the issue in the international scene after the spanish defeat, thus the recognition of the Sultan's rights.
If we want an spanish Sabah I think we need a POD some time before, maybe if, for some reasons the british have not interest or means to strnght their presence in the zone...but we have still the Dutchs. Spains, for his own, can't do nothing against the british. It would be against the spanish doctrine in international relations at the time (more or less with France and Britain when they are together, neutrals when they are opposed) and it would be a suicide if Spain goes to war against Britain.
I can't help you in that question because my lack of knowledge, but I think in any scenario you should take into account two major limitations to the spanish military capabilities and ambitions (and not only military). Obviously the lesser industrial basis compared to the main competitors in the world stage (and the lesser manpower) and the chronic budget deficits runned by the spanish state during the entire XIXth century, except for four years. On the other hand, no spanish-american war probably means a bit less worse economical situation for Spain and specially less pressure over its public debt (I'm talking about 1898, not the present), but not enough to boost too much the spanish power. So, probably the size, equipement and training of the spanish armed and naval forces would be similar to OTL, or at least not much bigger, I guess. But I don't know how they would be distributed in TTL.
I also mostly agree with Tocomocho's scheme, but I think it could be nuanced. The internal tensions are still there with or without spanish-american war, and even in the eventuality of a spanish victory in the war they would be there. So, in TTL Spain wouldn't be neither a haven of social harmony. There is a huge agrarian problem, probably the deeper in europe at the time, a deficient pseudo-democracy which managed to integrate groups of interest excluded during the reign of Isabell II but still avoided the social question and didn't help to create a climate of confiance in the parlamentary system among the masses. The democratic revolution of 1868 and the First Republic troubles didn't come from the vacuum and many of the forces behind it were still alive. Furthermore, the anarchist and socialist movements were gaining more and more ground at least since the 1870's (that's not in principle very different to the rest of Europe) and the voices calling for a "regeneration" of the country predate the disaster of 1898, although it boosted them. Also, the deficient national and economical integration , the regional disparities and selfish regional groups of power (which were the spine of the Restauracion's regime) are still there. In my opinion, in the more optimistic case in TTL Spain could aspire to be a poorer but less tacky version of Italy, and that's not a good prospect and it even seems unlikely.
Regarding Morocco I have doubts. On the one hand, there were sectors during the second half of the XIXth century who considered that the natural frontiers of Spain were in the Atlas mountains through certain weird historical interpretations, among them Cánovas himself, but I'm almost sure they were a minority. On the other hand, if the interests of the catalan bourgeoisie in Cuba and Puerto Rico remain intact, probably there will be less interests in new colonial adventures. Although Spain had still economical and strategical interests in the southern neighbor and precedent and frustrating conflicts against them. Additionally, the disaster of 1898 served to realize about several deficiencies in the spanish defensive capabilities. That's also related with your previous question about the colonial forces. It was clear that defending a flank of the spanish territory (the Atlantic or the Mediterranean) would mean exposing the other. Therefore, if someone realizes these problem without spanish-american war, I suppose Morocco would play some role in the mediterranean defence, but I dont know in what way. Anyway, as said before, the spanish ambitions would be limited by the spanish capabilities.
And regarding Cuba, I agree mostly with you. but also I think a negotiated solution to the conflict would be necessary and wanted by both sides, maybe a remake of the Zanjón peace with steroids granting large autonomy to the Island, as other have suggested. A long conflict was against the economical and political interests of both the spanish government and (specially) supporters in Cuba and the rebels, leaving aside the foreing investments in the island which perhaps could have lead to ulterior international pressure over the spanish authorities to make a deal.
Cheers.