Yes, with your keyboard you can write Spanish texts. And fhere is the Ç character which is frequently used by Portuguese, Catalan and French.

But for Catalan, you'd need the ` (accent grave) working as a "dead-key". Can it be written on your keyboard? (I guess that the accent on the G key is the accent grave). There is also the need to enter the Catalan Ŀ and ŀ characters (either with the · (middle dot) or with the Ŀ character).

For Portuguese texts, there should be some more dead-key accents, such as circumflex ^ and tilde ~. I cannot find them (the photo is not clear enough; can you add a clear diagram or picture with clear key labels?). But I guess that the accent on the T key is the circumflex. And is the tilde ~ on the Q key? On the Englsh keyboard the ^and ~ don't work as dead-key accents, but I assume that when the input language is set to Portuguese, for example, they would work correctly.

The use of the ª and º ordinal indicators is not limited to the Catalan language - they are found also on some other standard keyboards (Spanish, Italian ...). But no problem, your keyboard layout includes them.

So, it looks that all the characters and accents of the three "Iberian" languages can be added to the keyboard without making its use any more difficult for English texts. Perhaps the Ç character could be entered with a dedicated Ç key (but then the layout would become rather "Latin-American + Iberian" than an "English+3" layout).