Equipment isn't also just rifles. It also ammunition. You have rifles but not enough ammo. Not one time delivery ammo. Those ammo are not enough for a long term assault.
The Philippine economy is larger than the Chile economy at this time. But the only direct control Aguinaldo will have is Luzon minus Manila, Baler. All of the other islands can be intercepted by the US Navy. The question you must put is if Aquinaldo is economically competent to squeeze taxes to buy this in short of amount of time from the Surrender of Manila up until Feb 1899.
Always remember the one who had training to train an army is Luna. Remove Luna, Katipunan members wont be able to train them not unless they hire a lot of former Spanish army soldiers, Insulares who were members of the Spanish army. This important since you also have Filipinos dying, and you need a large reserve to fill up the slots of dead Filipinos.
Luna maybe inexperienced but is very well versed on Western tactics. Tactics which Aguinaldo isn't trained for.
In battles Aguinaldo won, numbers where 1:1 and casualty rate vs Spain is 1:1 wherein the Philippine side is on the defensive. But Spain also had irregulars at their side.
The casualty rate of the US is too high 10,000. in your February 1899 battle. US are on a defensive on a fixed position supported by heavy artillery from the ships. Without neutralizing the US navy, there is no way to win it due to firepower of the ships not unless Philippines started buying large artillery pieces which the US wont necessarily provide and more expensive than rifles and bullets. You can only deal 10,000 with enough artillery firepower.
Even with a trained force, the Filipinos can hold a certain line outside the range of Naval artillery. From their on, it is more equal due to training. Without neutralizing Naval artillery, Philippines cannot deal heavy casualties vs the US forces.
Like I said before, if you train and arm enough Filipinos to US army levels, the US diplomatic policy might change by December that your battle wont happen. US decided base on OTL that the Philippine army was weak, untrained, lacks equipment.
Now, if you wanted the battle to happen, US will win in Manila, but once you are outside the Naval artillery range it is a toss coin vs a well trained, equipped army. But that wont happen if you let a lot well trained Filipinos die in Manila. Remember Filipino trained manpower is lacking. By that time, it is a matter of attrition and propaganda. If Philippines loses the propaganda, US have so much resources that attrition to them wont matter. Propaganda means reporting high casualty rate in the US,etc.
I believe this same scenario happened vs the OTL British. British won in Manila but was dragged down once they reached Pampanga. At least around US 2 years they stay in Central Luzon. That would put the casualty rate of the US higher both vs trained army and tropical disease, give enough time for propaganda to hit US to give up on the war.
