Wow, so in addition to not plundering Portuguese ships and territories directly, they don't have the incentive to colonize the Dutch Antilles and Guiana (so salt, and not the sugar or tobacco trades was the Dutch motive, eh?) I imagine if the Dutch are not in the Caribbean, the English or French will grab their share of Guiana. Who would end up with the Netherlands Antilles? The Spanish Main (New Granada) is closest, but the English or French might want to grab some additional available Caribbean islands. Or the Danes, or Swedes or Courlanders. Or Tuscans, Sardinians or Sicilians for that matter.
If they really stay uninterested in substituting for or eliminating Portuguese middlemen, seeing them as a more reliable and trustworthy partners than even England or France or Spain, then the Dutch may not grab a bit of Africa or Asia at all. Might the Dutch sit out establishment of colonies entirely? Seems kind of hard to believe, but stranger things have happened.
Their initial interest was the saltpans along coastal Venezuela. Salt was a valuable commodity and was needed to preserve herring along with meat. Salt could be obtained from France (Britanny), but was unsuitable for the herring. The Netherlands traditionally acquired this salt from Setúbal due to its low price and high quality. The search for salt really only began once the Portuguese salt was cutoff to them by the embargo of 1598. The first voyages to the New World soon commenced as necessity is the mother of invention, and by 1600 they began acquiring salt in large quantities from coastal Venezuela. However, once the embargo ended between 1609-1621 the salt trade with Portugal resumed and no salt came from the Americas.
To not bring empty ships with them, the Dutch began importing goods to barter (knives, utensils etc) with the natives for tobacco, hides and dyewoods from Guiana. However, they may have not stumbled upon this with a steady supply of salt. With the resumption of hostilities in 1621, the Dutch began acquiring salt once again and decided to establish permanent settlements in the region during the 1630s. However, in 1630, the Spanish governor ordered the saltpans flooded, leading the Dutch to take Saint Martin in 1631.
The Dutch attacks on Brazil too were largely the effect of the Dutch being cutoff from Brazilian sugar. The Portuguese had even allowed Dutch ships to carry sugar to and from Brazil prior to the embargo, as the demand was too large to meet. Once they took Recife in Brazil, few Dutch settlers went to the area though.
As for expansion in Asia, it appears that in the 1580s the demand for goods from Asia was so great that the Portuguese were unable to meet the demand. So this could certainly lead to the the Dutch establishing their own trading posts or factories. On the other hand, the Portuguese may allow Dutch ships to trade directly with its colonies as they are unable to meet the demand.
What did occur due to the embargo though was the founding of the East India Company in 1602. From its founding until the 1609 truce, the VOC was largely an instrument of war, rather than of commerce. "In fact, the subsidies it received from the federal government of the Netherlands were not nearly enough to cover its military expenses and, after the first twenty years of operation, the debt accumulated by the VOC nearly equalled the capital outlay of the company" (Emmer, First Global War). Around one-half of the company's profits between 1602 and 1609 came from piracy (1 million guilders per year).
Between 1597 and 1609 the Dutch captured 30 Portuguese ships in Asia, representing around one-fourth of Portugal's Europe-Asia traffic. However, during this first period, the tonnage of goods arriving from Asia in Lisbon remained constant, so it can be summarized that the Dutch were only able to prevent further Portuguese growth during this period. One also has to remember that Dutch piracy forced Portuguese ships to sail at dangerous times, denying them access to Saint Helena and Terceira, and closing Goa and sometimes Lisbon with blockades, raising the costs of shipping.
Portuguese shipping was much more vulnerable to piracy than Spanish shipping simply because the Portuguese were sailing with goods, that were often perishable year round (sugar, slaves, spices, silks, etc). The Spanish on the other hand collected their bullion from the Americas and sailed them in large well armed convoys across the Atlantic and Pacific with less frequency. Making them much more difficult targets for privateers.